Most of the time, Slain will wear a variety of broad trenchcoats or cloaks, slitted at the back to allow for his wings. These can be any color from red to maroon to black, and are always open at the chest. He wears rather worn black leather breeches, rarely black vilam, and no boots due to his sharp-taloned paws. He also wears his sword, Visis, across his back - and a slim pair of pendants around his neck.
During the Hell War, he was also granted the form of a human; tall, with a similar, muscular build to his anthro form, he sports tousled white hair and scarlet eyes not unlike his brother. However, compared to his brother, he appears to be older and has chiseled facial features rather than Jekt's refined face. He likes to wear black leather and sparse silver armor, though is most often found bare-chested (or shirtless).
To those he cares for, he is fiercely overprotective, to the point of harming others who get in the way of the welfare of the ones he loves. He isn't above killing for family, and has done so many times before, with varying results.
Lastly, he likes to joke around and have fun with friends. He's a huge flirt, loves women, and will go to great (sometimes inconvenient for others) lengths to impress someone and show off. He's a thrillseeker, and will go find the biggest, baddest, most hideous demon to kill just for the hell of it; a habit that friends and family have long since stopped trying to break him of.
His favorite weapon in close combat is that of his blackmetal sword, Visis - made from a mix of carbonized meteorite and dragonsung steel, it can cut through nearly anything, and has served him well for many years. It seems to have a mind of its own, and won't be wielded by anyone it doesn't accept; Slain is able to summon it and banish it at will, usually pulling it from the air when he isn't wearing it across his back. Its pommel and handle are made from regular dragonsteel, set with rubies and wrapped in black leather.
In addition, he has strong sense of his aura, and is able to utilize it in silver flames shot through with crimson lightning. Often, he;ll use one or the other - he learned long ago to 'separate' the two colors of his reiatsu, and found that each has different effect when used. He can use the fire as a defense or offense, able to decimate wide areas with ease - or the lightning for direct, pinpoint attacks that create instant, lethal damage. Unlike normal lightning, the crimson bolts can't be deflected, redirected or absorbed, though the fire acts much more like normal flame. As an offshoot of both, he can also summon a 'shadow' of his aura - crimson smoke that often appears as ghostly flames. This he uses as a personal defense, or a stealthy offense, since many cannot see it.
His wings' webbing turns into sharp, featherlike planes of light, blinding to behold and reflected tenfold off of each scale. His horns and claws grow in length and gain the appearance of sharp, black blades that can be extended or retracted at will, made to any length; his bladelike scales share this trait. His tail splits into three, each tipped in blades and fire. Lastly, his fangs and eyes turn black and his mane curls in glistening white flame, crawling down his shoulders, wings and back.
The way it works is very simple - when his true name, Martyr, is spoken (either by him or another, it doesn't matter), he is inflicted with the wounds of the most severely injured near him, usually within a thirty meter diameter. Because of his healing gene, where his injuries heal at an incredible rate, he heals almost instantly from even fatal injuries, and uses this to save those fighting around him. However, using the Curse too much will begin to weaken and slow him, until he is too exhausted and on the verge of a Trigger.