Ok this is a guy i used for a little bit in an old forum which was never really active. Let's see if you think it can fit in. Most of his abilities are weapon/item based just for the record
Age:105 (just gonna make this an earlier part of his life. about 70 years after he signed the contract)
Known languages: Common, all human based languages, Abyssal (the language native to the plane of the abyss)
Appearance: Usually travels in a faded cloak that hangs to just above his ankles and shrouds his face in darkness. Without his cloak he is dressed in light leather armour that was made from the hides of the victims in the abyss. It was dyed black and he wears a shirt of chain-mail underneath it as well. He has Silver hair that is cut short. His eyes are green unless he begins to use his dark energy then they turn black like a demon. Pale and tall (5'10" ?). Agile and not muscular.
a general idea
Personality: Likes a challenge. Shows no mercy on an opponent no matter who they are. Calm and collected most of the time and hard to get angry. When possible, will strategize and plan out multiple courses of action before deciding on one to follow.
Lámina de la Muerte or blade of death. This weapon was forged for Rickamaru by arts known only to his sensei. It was a gift to him to commemorate the completion of his training. The blade never becomes dull and doesn't rust. Liquids of all kinda are incapable of sticking to its surface and just slide off. It also has the peculiar property that prevents any wounds it inflicts to continue bleeding unless extensive healing is performed. It is able to cut through simple weapons and armour as if they were made of paper.
Kunais/throwing stars. Rickamaru carries around a pouch of projectiles on his left leg that contain various poisoned weapons. The types of poison on the blade differ greatly however. Some are treated with a deadly poison while others merely induce paralysis. Other still can affect one's short term memory resulting in permanent loss and a short coma. This allows for Rickamaru to fade into obscurity easily and better cover his tracks when trying to avoid detection.
The Demon Scythe. The bundle that Rickamaru carries on his back is a scythe that has had its power sealed by the wrapping. Should Rickamaru's dark power usage spike really high the scythe will activate on its own otherwise it must be unwrapped first. The scythe is a weapon forged in the depths of the abyss which Rickamaru's master presides over. It is a flawed demon weapon that, while unsuitable for a demon to use, is far more powerful to a human servant. So Rickamaru's master gave the weapon to him and told him of the power it has. It was then attuned to his being so that only he could use it.
-Elemental Jewel Craft: Rickamaru has developed and mastered his father's legacy and is able to infuse raw elemental energy into special crystals. He can tap the power stored in them to use many abilities or to recharge his own energy.
Dark abilities (main form):
Main ability: Rickamaru is able to create portals of dark energy at any location. These portal link to the realm of his master but by utilizing two portals he can travel between locations he has coordinates for. He must step into the demon realm before he can exit another portal. Others who enter one of his portals must chance discovery by his Lord and even if with him will only have a limited protection,
Dark Meld: This ability allows him to meld into the shadows and the night making him completly invisible (ninja)
Night Eyes: He can see in complete darkness
Hatred of the Light: Due to his demonic based powers, he is extremely vunerable to light based abilities. Works well when he needs healed however. As a result however, if normal healing arts are performed on him as if this ability did not exist, then this will cause an immense power surge which more then likely will activate the possession mode.
Ageless: he doesn't physically age but he can be killed normally.