Summary: A representative from hell arrives and attempts to cause trouble with Catherine's contract. Something she will not allow. However, a half demon witch cannot hope to fully crush a fully-fledged demon, right? But someone who is more demon than any other can. Sebastian cannot accept anyone picking on his little sister.

'Catherine, what is that?' Elizabeth asked fearfully, looking at the falling black feathers that suddenly began to appear, halfway into their training.

'A demon is appearing. A filthy one.' Catherine hissed, pulling Lizzie back away from the slowly materializing man. When the last fear fell, it revealed a man with long jet black hair, silver chains and a collar on his throat.

'Hello, pretty demon witch.' He greeted with a devilish smile. Catherine narrowed her eyes. 'I'm here on behalf of the Great Lord, you see, we're not entirely sure a half creature should be able to from contracts.'

Lizzie toughened up and pointed to him imperiously, her other hand ripping off the ribbon around her neck, showing off her contract seal. 'Catherine, send him back to where he came from.' Catherine twitched. It was a difficult order. This demon was powerful and magic can't affect it. But she couldn't refuse.

She poised her hand over her chest, tugging off her glove with her teeth. 'As my lady wishes.'

Lizzie backed into the house and watched. The battle begun. Lizzie began to fear when all magic could not harm him. Still, Catherine was an impressive demon and the man was breathing hard as was she. The difference is this Catherine had a trickle of blood at the corner of her mouth. She was quick and strong, full of wits but then fighting this particular kind of demon was never easily and witches were still classified as human which she was half of. She's a fast healer but not quite as fast as Sebastian.

'Give it up, I'll kill you if I have to.' The man laughed, knowing he could win even if it would be difficult.

Catherine smirked anyway, thinking quickly. She could still cast spells on herself which was what she did, very silently. 'My lady makes a good apprentice and I won't lose such a convenient tie to my brother.' The man paled considerably.

The demon man growled at Catherine. 'Your brother is not here to save you now, demon witch!' His demonic weapon came down hard upon Catherine for the finishing blow. A clash of metal resounded.

A large silver scythe stopped its descent. 'But I am.' A smooth voice answered easily, almost cheerily. Undertaker grinned and chuckled. 'My, my, it seems you've gotten into a bit of trouble, my dear.'

'Undertaker!' Catherine exclaimed in surprise. Had he sensed the presence of a new demon and come? She definitely hadn't called him. She expected her brother sooner.

'A gentleman should never hit a woman.' Undertaker chided in a childish tone. The demon man grimaced, recognizing the legendary shinigami. Undertaker's smile turned into something eerily sinister. He took a large swing at the demon. 'I'll just keep an eye on this little troublemaker until her brother arrives.'

Catherine struggled not to collapse. It wouldn't do to frighten her apprentice, even if her insides were crushed, bruised and broken. Suddenly a strong presence was there behind her, holding her up with both her hands. She looked back and saw her smiling brother. 'The trouble you get into, Catherine, really. I suppose I must thank the shinigami later.'

And in the next moment he was fighting, taking on another demon, his face smirking but eyes red and fierce. Undertaker stepped out easily, taking Sebastian's previous place behind Catherine. She leaned back against the shinigami slightly, watching the show.

Demons were created in pairs and the essence of which was supposed to be split into two equal whole pieces. The idiots in charge of this had split Sebastian and Catherine's unevenly. Instead of two wholes, Sebastian had three halves and Catherine only had one. So while Sebastian was created as a being beyond any other demon, Catherine's creation was held back until they ripped out half a witch's essence and merged it with her demon one. It did make her one hell of an interesting person though.

'So you are the brother. Sebastian Michaelis, we heard was your new name.' The man spoke, nervous now that he had to fight Sebastian after I had weakened him. Sebastian pinned him to a tree with an array of forks and knives.

'Yes, I am. Now don't forget.' Sebastian warned with a creepy smile as he approached slowly, his canines peeking out. 'Tell your friends, I won't tolerate anyone harming my sister.' And with that Sebastian stabbed a knife through his forehead. When he moved away, Catherine set the demon's body on fire, sending it back to hell swiftly. Her face showed nothing but she made a point to heal herself later.

'Catherine!' Lizzie called out, running out of the house and crashing into Lizzie. Catherine almost cursed with the pain of the impact but she slid down to her knees and poised her hand over her chest with a smile.

'Don't concern yourself, my lady. It is taken care of.'

'Thank you!' she squealed, hugging Sebastian's legs. The demon butler's eyes widened in surprise. Lizzie had been cold and intentionally avoiding him since the day she found out he was planning on devouring Ciel's soul. She did the same to Undertaker but he merely patted her hair and with a quick goodbye, he disappeared.

'Lady Elizabeth, Master Ciel has requested your presence. Why don't you go ahead while I tend to my sister?' He suggested serenely. Lizzie nodded her head and ran off, looking for her adorable fiancée. The moment she was gone, Sebastian scooped up his sister so she wouldn't waste any energy on walking.

'It's been quite a while since you carried me, brother.' Catherine said smartly, already beginning to heal her damaged body swiftly and efficiently. 'I hate it.'

'Excellent, it won't be happening very often.' Sebastian replied simply, a smile of approval on his lips. He liked how she managed to find perfection in her pride. By the time, the two siblings caught up with Ciel and Lizzie, Catherine was healed to perfect health. But she knew Lizzie and Ciel watched her carefully, searching for signs of pain or perhaps worries over what happened.

'Catherine…' Lizzie started, sounding rather upset.

'Please do not worry yourself, Lady Elizabeth. Catherine is... despised by some from our world because of her origins. She isn't a true demon which is why she failed to fight that one off alone.' Sebastian said with a peaceful smile. Catherine shot him a withering glare, her eyes red.

'Not quite accurate.' She corrected her brother. She hated when anyone implied that she was weak. 'I can defeat any shinigami or otherworldly beings and many demons. Some demons are unique though like that one. They carry immunity to magic. That is all.' She said, the last sentence hard and directed at Sebastian.

'I thought you were going to die.' Lizzie said, her voice half relieved half fearful.

Catherine let out a small laugh and Sebastian smiled widely, chuckling under his breath. Ciel and Lizzie continued to look utterly confused. 'Inconceivable. I'm immortal.' She said freely.

'In more ways than one.' Sebastian added and his tone was mixed with something dark and secretive.