The creature's vocabulary is limited to other beings' words, which raises questions all its own. Giratina makes no move to interrupt, though, as piece by piece, echo by echo, the creature gives as clear an overview as it can of a town by the sea. It explains about the way a species descended from humans fell to conflict after the discovery of a blood that can cure any illness, about the nightly hunts of mortal-borne monsters, about the watcher in the moon who sponsors the hunts.
Aside from a single offhand reference to being human that Giratina attributes to an error resulting from its method of speech, it skirts over mentioning itself. For a human to know these things, to be able to speak even in such a constrained form about them, isn't conceivable. There are days Arceus can't understand its firstborn three, because in learning to socialize with humans and the younger pokémon it must by necessity abandon vast swathes of its own experience; there are aspects of the universe so alien to the current generations that merely possessing knowledge of them makes for an insurmountable communication barrier.
After the last stroke of its choppy description, it trudges back to the first rune and sets about erasing its work. It seems such a tragedy, in that moment, that it has no voice of its own, that it should understand as so few in all the universes do and yet still not know enough to speak. What would the creature's own voice look like? What would its first word be? A few more pushes to bring it to the edge, and perhaps...
It makes a quiet sound in the back of its throat. It writes of a graveyard filled with flowers, lit by the moon's grace and nourished by an oath made in a different lifetime. There is a promise. There is a purpose. There is a home that treasures it and welcomes its return, the creature its companion through the long nights.
...no pushes, then. Giratina dips its head closer to the snow as if a different angle will present some method to misinterpret that final word, but its meaning is quite clear. The clearest, in fact, nothing but deep lines and clean edges, the straight line and the slanted square it bisects.
It turns its eyes to the creature, who straightens under its focus. Giratina didn't notice earlier, but most of its weight has shifted onto its projectile launcher and left leg, the one with a foot, since it touched ground. Favoring an injury. Life tends towards symmetry in form; whatever the creature is or has the potential to be, it seems not to be exempt from that particular pattern after all.
Giratina cannot return it to its home world. For one, Giratina doesn't know how it could have arrived here in the first place if not through a portal; for two, the dragon can't place its world. It made no mention of pokémon in its descriptions, which sets it as too far from the origin for Giratina to reach without leaving the Distortion World untended for a dangerously long time. But the cosmic beings sound uncannily like pokémon from the generation that followed Giratina's, even though the dragon's certain it should know everyone from that age.
Palkia can locate and open a portal to the universe. With some difficulty, Arceus can likely do the same. Giratina, however, has not sought peaceable contact with either of them since the humans in the bordering world learned how to use pokémon's abilities to help cultivate their food plants, and it would greatly prefer not to ever change that fact.
If the creature wishes to return, it can only find a method on its own. It's fully capable of doing so. It already came close earlier when it contacted the watcher through the ocean. Until then, Giratina can at least find a better climate for it. And do something about that leg as well, since the injury plainly inconveniences it.
Giratina tells it as much and waits while it etches. It seems to require writing as a bridge to comprehension. Or perhaps it needs only time to understand, the writing nothing but a supplement, as partway through the word it rather suddenly (and disappointingly) breaks off, shifting into a pale mist that reforms well out of Giratina's immediate reach. Did Giratina scare it somehow?
But of course it has no way of telling the dragon should that be the case. Giratina asks regardless, and after a pause the creature lets its weapons hang at its sides, though it takes another step back. If it wants to put much more distance between them, it'll have to move to a neighboring isle.
It's so small. For some reason, Giratina's mind keeps catching on that fact. The dragon has no recent experience actually interacting with anything of this size. Or, no, its size isn't the issue. Necrozma, who Giratina's familiar with for the number of times it's had to clean up after the light-eating pokémon's rampages, isn't very much larger, but it has never held itself like it expected to be blown over should someone like Giratina pass by too close to it. The dragon's watched it throw itself into battle against pokémon of comparable size without hesitation.
And now it watches the creature do just that as well.
The attack comes from so far out of left field that Giratina doesn't even think to phase and only even rears back purely out of reflex. The shallow cut it receives down its front is more bewildering than painful.
The next, from underneath, is the opposite. Giratina passes into shadow and materializes farther above the island, coiling around its wound. Blood sinks into the snow, into the white space that was so recently occupied by the creature's echoes. The creature itself is nowhere to be seen, but this world is Giratina's domain; it screams, long and high, and the gradients of the Reverse World's silence return an answer.
The creature's concealed itself perfunctorily under the overhang of the cliff, barely out of the dragon's line of sight. Giratina considers retaliating—it's only natural that it should take offense at such completely unprovoked aggression.
Eventually, it decides against it. It still has questions it's curious about, and no real harm was done. The scratches will heal.
It's a mystery why they were inflicted in the first place, but Giratina rather doubts the creature will answer if asked at this point. In any case, it plainly doesn't want the dragon near it; it does, however, still need to be relocated, since its wispy build should not in the least suit it for extended stays in colder climes. Simply snatching it up again now that Giratina knows it can speak seems rather crude, though.
Well, the dragon can hardly be blamed if it will not use its speech. Turning to violence before words is the sort of unflattering behavior it expects from its siblings and creator and no one else. (Although – thinking on the matter, its siblings, at least, share a commonality with the creature of knowing no widely-used languages. But if there's a pattern, Giratina breaks it, and Arceus continues to have no excuse.)
It vanishes, sinking into the shadow beneath the cliff; the creature leaps away just in time as Giratina surges up from under it. It slashes the dragon as it passes, then moves quickly back and away from the dark tendrils that lash out to grab it.
Giratina hovers out of its range again and glances at the latest injury. Small and fragile it may be, but evidently the creature does know how to fight. Rather competently, too, considering its performance against an opponent who outclasses it to such an extent. The gap between them likely doesn't even faze it too much; if its tactics are anything to go by, it's accustomed to battling as the significantly weaker party.
Giratina usually counters more agile opponents through wide-area attacks of overwhelming force. That's not particularly applicable here – the last thing it would want is to kill the creature – which leaves the question of how it's going to catch the little thing. Paralyzing it would slow it down enough, but Giratina, not being naturally inclined towards producing it, can only muster up so much electricity before it'll need to rest.
Earlier, Giratina grabbed it while it was falling. Whatever its maneuverability on the ground, it has no method of changing course in the air. Giratina considers the angle. It's come out from under the cliff, which will make things simpler.
The dragon phases and reappears at the base of the cliff, putting the creature's back to the edge of the island. Giratina merges the tendrils on its back into wings and brings them forward, threading its own essence into the draft as sustenance. The creature staggers beneath the wind before it pushes its blade into the snow to anchor itself, refusing with annoying tenacity to allow itself to be blown off the island.
Giratina takes the moment while it's off balance to hurtle forwards. The creature turns into fog. Giratina winds around, and as soon as the creature reforms swings its tail; the creature ducks, dematerializes again when the tail comes down and smashes a pit into the snow, and darts to the side when tendrils reach for it.
It moves in for an attack, and Giratina calls up a shield. The expanding bubble slams it back while Giratina twists to face it, sparks glowing between the dragon's spread mandibles. The creature rolls to its feet, then sprints towards the wave of electricity, losing its form just as the attack reaches it.
Giratina thought the fog was similar to a vaporeon's ability to become water, but it must be closer to Giratina's own skill: rather than turning into a different state of matter, what it's doing is momentarily displacing itself from reality. The dragon tosses up another gust before the creature reaches it, then bends down to pick it up – except, of course, it phases again and hurries backward, giving itself some illusion of distance.
Sustained wide-area attack of overwhelming force. Giratina is sorely tempted.
The creature doesn't make another move. Experimentally, the dragon starts to form a shadow ball between its mandibles; the creature shifts its stance, but nothing else. Giratina lets the energy dissipate, and the creature visibly tenses.
After a long stillness, it starts gradually to settle. Giratina eyes it dubiously. It attacked first; what justification does it have for wariness now?
It takes a single step closer, acting like it expects Giratina to send a hyper beam its way any instant. It looks – and Giratina actually blinks at the strangeness of the notion, but – it puts Giratina in mind of the way the dragon itself acts around its creator. During the rare interactions where they aren't trying to maim each other, in any case.
Though comparing itself to Arceus is...
Unceremoniously shoving that thought aside for the moment (and all foreseeable future moments), the new perspective does frame the attack in a rather different context. Something it did clearly set the creature off. The dragon said something that unwittingly agitated it, and the creature's grasp of speech is limited enough that it has no words available to it that could explain the cause of its distress.
So: violence, the universal language.