Mooks were probably the most pathetic creatures on the Rock. They came from many worlds, and many different species. Probably the majority were human, but there were also orcs, goblins, flying monkeys, wolves, hyenas, toads and many more. Whatever their species, the most noticeable thing about them was their blankness. Most of them had no names, no families, no personality or interests, and not much intelligence. When they had died, there would have been nobody back in their home worlds who mourned their deaths, not because they were hated, but because they were uninteresting. The sole purpose of their existence was to serve as the minions for some villain or other, and be killed by the hero.

What made them most disturbing was not their aggression, or the crimes that any of them might have committed, but the fact that almost anyone, under different circumstances, might have been a mook. Well, not anyone, exactly. Severus couldn't imagine Anakin as a mook; even to people who didn't regard him as a potentially redeemable human being, but simply as an evil Dark wizard in a mask, he was a specific, particularly terrifying evil Dark wizard in a mask. Severus didn't think that he himself could have been a mook, either. But Konstantine – maybe. To people who didn't have a personal reason either to love him or hate him or feel sympathy for him, it would be easy to see him as just another pitiless Barrayaran soldier wielding a nerve-disruptor.

Mooks were people who were barely aware that they were people, because no-one had ever shown them that they were. When they arrived on the Rock, usually as part of a group who had been massacred in some battle or other, the organisers of the Rehabilitation Centre would generally find them a dormitory where they could stay with their colleagues, but start looking for foster families who could give them individual attention and love, while they continued to return to the Rehab Centre each day to see their friends and attend classes and have individual and group therapy sessions. Unfortunately, there weren't many people who were interested in fostering mooks – and orcs were the hardest to find homes for. So it wasn't surprising that Nutt, who had already been working to rehabilitate and educated orc slave-soldiers and orphaned orc children on his home planet, was now doing the same for the orcs who had found an afterlife here after being slaughtered by adventurer parties.

There was a long timetable of classes posted in the foyer. Severus wondered whether mooks were expected to decide for themselves which courses to study, or whether new arrivals were just randomly assigned to a range of classes until they started to show preferences. Hogwarts usually started by teaching core subjects like Potions, Defence Against Dark Arts and Transfiguration before students chose a wider range of subjects to study from their third year onwards, but Severus was aware that some Muggle schools did it the other way round, assigning first-years to a wide range of subjects for one hour a week each, so that students narrowing their options down to ten subjects for the Muggle equivalent of OWLs would already have some idea of what they were interested in.

At any rate, by jumping onto a table and standing on his hind paws he was able to read the list of classes and establish that the ceramics repair class was held in a greenhouse, for some reason, on Monday mornings at 9am. He arrived as the class was starting, and managed to slip in between the hooves of a hulking minotaur – why did it even have hooves? Weren't minotaurs supposed to be human from the neck down? This one looked more like a humanoid bull, with cloven-hoofed hind feet and a tufted tail, and hands that looked human except that, for no reason known to man or cow, they had claws. It – well, no, definitely he, as Severus could detect from the smell even before its kilt gaped open – sat cross-legged on the ground, and the other members of the class trooped in and did the same. There were three orcs, one bright green with pointy ears, one swarthy with tusks and a nose-ring, and one blue with a flattened nose and numerous spikes projecting from her face which could have been either natural features or jewellery, two green goblins, and three kobolds, one lizard-like, one furry with a cat-like head, and one the traditional bright blue humanoid.

Nutt looked – well, squinting at him, Severus realised that he was projecting a different image of his size to different members of the group. To the minotaur and to the largest of the orcs, he looked as massive as they were (around 7 feet tall) and thus deserving of respect, but to the goblins he looked around 3ft 6, and to the smallest of the kobolds he appeared no more than 2ft 6 and therefore unthreatening.

'Now, you have all done well in practising repairs with simple adhesives, and it is time to begin using the traditional Counterweight Continent style of kintsugi, using urushi, the sap of the lacquer tree,' Nutt began. 'Do you remember what I said last week about urushi?'

'Burns the skin,' said the swarthy orc.

'Well done, Mr Wurgoth Bloodguzzler! And therefore…?'

'Need to wear gloves!' said one of the goblins. 'And a mask, 'cause it's poisonous to breathe in.'

'Good, Miss Doinqea, and what do you have to remember when wearing gloves?'

'Keep claws in,' said the cat-headed kobold, holding up a paw.

'Good answer, Miss Tinkernook, or if your claws aren't retractable?'

'File blunt so they don't tear the gloves,' rumbled the minotaur.

'Excellent, Mr Zanur! I didn't even realise I had claws until I was an adult,' remarked Nutt reflectively, extending the claws of one hand and then sheathing them again. 'I was terrified the first time they sprouted. But I soon learned to keep them under control.

'Now, can anyone remember what else I said about urushi, and why craftsmen of the Agatean Empire use it?'

'Takes a long time to set,' said the lizardlike kobold.

'Yes, that's very true, Mr Kovo. So, what are the advantages of using it, compared with glue?' Everyone looked blank.

'Anyone? Mr Shelgra Gnome Dissector? Miss Kathil the Shadow? Miss Griegnoilmail? Miss Thrahs Mountainchewer?'

The blue orc raised a hand.

'Yes, Miss Kathil the Shadow?'

'Oh, is that me?' said the orc, disappointed.

'Yes, that's right. Do you remember what we discussed about the properties of urushi?'

'No, I just wanted to ask what my name was again. Which one is Thrahs Mountainchewer?'

'That's me!' said the blue kobold.

'Is it? Can we swap names?'

'No, you can't!' retorted the kobold. 'I don't want to be called Kathil!'

'If you wish, you can both name yourself Thrahs,' suggested Nutt gently. 'Names do not have to be unique identifiers, nor are they necessarily permanent. The "Choosing a Name" class was more an exercise in choosing than anything else. Could you both take the name Thrahs, but choose different identifying titles?'

'All right. I'll be Blue Thrahs,' suggested the orc.

'But I'm blue Thrahs!' retorted the kobold.

'No, you're Thrahs Mountainchewer. You said,' grumbled the orc.

'We seem to be at an impasse,' observed Nutt. 'Can anyone think of a solution?'

'Why can't she be Big Blue Thrahs,' suggested Zanur the minotaur, waving one massive hand at the orc, 'and she be Little Blue Thrahs?' as he indicated the kobold.

'Call Big Blue "Beebee" and Little Blue "Ellbee" for short,' added the goblin who wasn't Doinqea.

'No, I'm not being Beebee! That's a stupid answer, uh…'

'Griegnoilmail,' filled in the goblin helpfully.

'Yeah, that's a stupid idea, Griegnoilail,' said the big blue orc.

'I think Wurgoth is right,' said the blue kobold. 'I'm okay being Little Blue Thrahs.'

'Okay. I'm Big Blue Thrahs Mountainchewer.'

'Well done! You're all getting much better at problem-solving,' said Nutt. 'Now, can you remember what I asked you before we discussed names?'

This, Severus reminded himself, was a polymath who, despite having taken a job as a lowly servant in a wizards' university, was at least as as erudite as the most distinguished wizards there. And yet he had the patience to instruct a class of monsters who barely had the intelligence of human five-year-olds. Had he been depressed to learn that not all orcs were as intelligent as he was? If so, he didn't show it.

'You asked if we could remember what was good about tree sap stuff,' said the green orc eventually.

'Well done, Mr Shelgra Gnome Dissector. And can you?'

'No.'

'Most of the glues sold in model shops are either poisonous, or can melt at high temperatures or dissolve in water,' explained Nutt. 'You can use them to repair a vase as an ornamental project, and they set as soon as the glue is dry. However, they don't make a resilient bowl for serving hot food or drinks in. By contrast, urushi takes weeks to set, and it needs to be kept in the right environment, with humidity between 70% and 85% and temperature between 25 and 30 Centigrade – between 77 and 86 Fahrenheit. But when it sets, the nature of the burning, poisonous raw sap is transmuted into something hard, durable and watertight which will leave the pot stronger than when it was originally made, and just as safe to eat and drink out of. Of course, if you add metals to the mixture, it retains their properties, so mixing iron ore into the lacquer will make it harmful to elves and unicorns, or dusting it with powdered silver will make it poisonous to werewolves. But other than that, it should be as safe as any other pottery, and much more interesting to look at, especially when decorated with gold.

'I have to warn you that this is a long project, as each layer of lacquer needs to take time to set. After today's session, we'll be placing everyone's project in a wooden box in this greenhouse, with a bowl of hot water to keep it humid, and coming back to monitor the temperature and humidity for a couple of weeks, until the pieces should be set and we can work on the next stage of repair work. Now, does anyone have any questions?'

Zanur raised his hand. 'You said last week – kintsugi is a metaphor for healing. That our lives heal from the scars of the bad things that have happened to us. That our scars do not disappear, but are part of what makes us beautiful. But healing only happens in the right conditions. So – if we learn something new that makes sense of our past, do we need to spend a fortnight resting in a hot bath while we think about it?'

'Stupid question!' hissed Severus, irritated. Why did the minotaur insist on taking a metaphor so literally?

But Nutt said, 'Well done, Zanur! Well remembered, and that is a very good question. It shows you're thinking about the philosophy behind kintsugi.

'Now, you must remember that metaphors only go so far. Healing takes place only in the right conditions, but they aren't the same for everything. A lacquer join on broken pottery needs to be left still to set, just as a broken bone needs to be immobilised. But your brains are made of soft tissue, like the muscles in your arms and legs, and so they need regular exercise to strengthen them.

'Of course, if you are constantly agitated and cannot relax, resting may itself be a skill you need to practise. But this is an active exercise. For example, golems who have been rescued from slavery need to have one day off per week to help them remember that they are people who have worth simply by being, when they are just sitting still, rather than tools that exist only to be used. Later on, when they have recovered from the trauma of slavery and found a job that they actively want to do, some may choose to work all day, every day, but this has to be something they do because they wish to, rather than because they do not know how to rest.

'Now, can you think of another difference between a person and a broken pot?'

The class pondered, wondering whether this was so obvious that it was a trick question, before Wurgoth said, 'Pots aren't alive. They're just things people make out of clay.'

'What about golems?' protested Griegnoilmail.

'That's different!' retorted Doinqea. 'Of course golems are alive.'

'But they're still clay that's been made into something by humans,' retorted Griegnoilmail.

'Watch it!' growled Big Blue Thrahs. 'Orcs were made by humans, too. You saying we're not alive?'

She meant it sarcastically, but Wurgoth looked worried. 'Aren't we?' he asked Nutt.

'There are different ways of being made,' said Nutt. 'We orcs were made by changing other living creatures. In my world, we are a mutated form of human; in some worlds, orcs are a mutated form of goblin or elf or even troll. Golems are made by shaping a clay statue and bringing it to life, but they are sentient people, so in that sense, as Doinqea says, they clearly are alive, in their own way. But on the other hand, they aren't the same kind of living creature that we are, so they don't have the needs of other living creatures to eat or breathe or procreate, and don't usually die, unless they are smashed to pieces in an accident – and if they are broken, they don't naturally heal themselves.

'So for now, for the sake of simplicity, let's discuss the differences between ourselves and an inanimate object like a broken vase. Shards of pottery can be mended, but they are passive. They don't have the innate tendency to heal themselves, as we do. But the disadvantage of our healing instinct is that it can heal in the wrong way: a broken bone can set in a crooked shape, or our minds may misinterpret an experience and draw the wrong lesson from it. And either can be hard to correct, later on.

'I was a slave until I was seven, when I was rescued and adopted. The first thing my guardian said to me when she saw me was, "You are worthless, but not unworthy." Looking at it now, as an adult, I can understand that she meant that I did not have the acquired worth that an adult has by being a useful member of society, and that I needed to learn in order to acquire worth, but that I had the innate worth that any child has, simply by being a person, which made me worth educating. But at the time, the words that spoke to me, in a way she never intended, were, "You are worthless," and I spent much of my life worrying that I could never manage to acquire enough worth to be fit to live. And so, later on, I had to unlearn the mistaken lesson and learn the right one instead.

'So I say to you: all of you have worth, the innate worth of children, because you are people. Everyone has the instinct to grow towards good as a plant has the instinct to grow towards light, even if we make mistakes because we are confused about what 'good' is. Even the worst person I ever knew was someone with something broken in his brain, who might have grown into a good person if he had let someone help him. But he had no wish to be redeemed. All of you chose redemption; the fact that you came here proves it.

'And you, Severus, have both acquired worth and innate worth,' he added.

Severus's pupils dilated in surprise. He had thought he was well hidden behind Zanur, but in any case, he didn't recall meeting Nutt since before he had changed into a cat. Was he so recognisable?

'I come from Überwald, like Angua,' Nutt explained. 'Many of the population there are vampires or werewolves, so recognising people in their different forms is an essential social skill. Recognising werewolves in wolf form is fairly easy, but recognising vampires who transform into an entire flock of bats or magpies takes rather more practice. And you are a beautiful cat, but, I must say, I still think you make a better human.'

What had being human ever offered him? Only a life in which he was nothing more than a tool. Other than by turning into an animal and refusing to acquire worth, how could he escape that?

'Incidentally,' Nutt said, 'you do realise that the Mook Rehabilitation Centre isn't the only place on the Rock offering adult education courses, don't you?'

Yes, he did. He had strenuously avoided being roped in to teach any classes. He had had far more than one lifetime's worth of being a teacher.

'If you return to being human and decide you would like to study something new – perhaps a course you did not have the chance to take when you were at school, or a new hobby – there are several organisations whose prospectuses I could give you. Or you would be very welcome to come here, if you wish to, and if there are vacancies on some of our classes. Being a mook is not compulsory, and it sometimes helps them to have a few outsiders in the class.'

Being an outsider yet again. And a student yet again, as if school hadn't been horrible enough the first time round. Severus left the greenhouse without a farewell miaow.

He had to admit (once he had found a neutral place to sit and think, on a neutral rooftop that wasn't too close to either the Mook Rehabilitation Centre or home), that he did dream of learning new skills. He did like Nutt – and even when he knew that the little orc was deliberately being as charming as possible, that didn't mean that Nutt wasn't genuinely a good person. If he was going to talk to any Mind-Healer, he would trust Nutt over anyone else.

Author's Note: I realise that in our world, the tradition of kintsugi comes from Japan, not China. The Agatean Empire on the Discworld is not China, but a composite of elements of different Asian countries, plus Asian-inspired western traditions like Willow Pattern porcelain, in the same way that Ankh-Morpork is a composite of cities and the Ramtops are a composite of mountain ranges. In the early books, I'm not sure Pratchett even particularly needed the Counterweight Continent to be Asian – Twoflower is mainly written as a European's stereotypical view of an American tourist exclaiming over how 'quaint' everything is, and Pratchett has said that the character of the Luggage was inspired by watching an American woman towing a huge wheeled suitcase. But, on the other hand, he needed Twoflower to be from somewhere with a visibly very different culture to Ankh-Morkpork, so giving characters names like 'Twoflower' and 'Ninereeds', echoing Mah-jongg tiles, was a way to achieve this. In the graphic novel adaptation of The Colour of Magic, Twoflower is drawn as a modern Japanese tourist, but in the film version he was played by Sean Astin, and although Pratchett was initially sceptical of the casting, he soon changed his mind. To me, Astin certainly seemed right for the part.