Henri Ackerman

Summary
Henri is a very tall, lean, and muscular nonbinary lesbian. They have short, dyed blue hair that they clip short almost daily. Henri is a computing prodigy and certified genius with an IQ high enough to enjoy Rick & Morty. They have a very strong sense of logical processing that's perfect for programming and organization. Henri enjoys programming, but maintains a well-balanced life, seemingly effortlessly; eating, sleeping, exercising, and socializing regularly to a degree that's noticeably better than most people. Henri is somewhat autistic, which shows in their flat affect, need for scheduling, and how they are prone to sensory overload.

Henri's mutation is that they have three pairs of arms, each with large hands with massive claws. These arms often get in the way of each other, in very inconvenient ways... Besides their mutation, however, Henri has an (at first) inexplicable supernatural ability that makes them immune to any mind-altering effect. This includes supernatural effects, such as from the Cursed Furby's corruption, and giving them the ability to see right through the The Perfect Disguise or the Somebody Else's Zentai. It also, however, includes alcohol and drugs, which they are completely immune to (aside from physical stuff; alcohol can still make them nauseous and hung-over.) Most notably, it means they remain in complete control over themselves when mutated by a Black Shard, though it is still very dangerous for them to use it...

The other power they have is a superhuman degree of empathy that they can learn to attune to: while they've always just assumed they were good at picking up tells and emotions and know what a person is feeling or if they're lying, they eventually learn to take it a step further and can tell you the emotional state of strangers from across the room.

History
In the hero's journey, there is often a mentor-figure who provides the chosen one with tools to help them complete their journey. A Chosen One is fated to oppose the Demon Lord (though fate is a tricky thing that often leaves room for multiple interpretations and possibilities). While Henri is not the Chosen One, they are a direct descendant of an ancient sage, and inherited a few subtle supernatural powers as well as a role of mentor for when the Chosen One shows up.

Trivia

 * Their arms make up about a third of their total body weight; for most people it's just 10%.
 * When they first mutated they only had four arms. A year later, their third pair grew in. They're still worried a fourth one might grow...
 * Really enjoys playing games by Zachtronics
 * They're really good at roguelikes and games that require careful planning, over games that require twitch reflexes and precision. They main Sombra in Overwatch and are good at carefully plotting out a place to hide, and strike at the right time. If Sombra is taken, they're also great as Bastion.
 * They're also really good at Crypt of the Necrodancer.
 * Due to planning out every hour of each day a week in advance, they can always find the time to work out regularly, despite being a computer geek.
 * Because of their supernatural "sage" powers, which grant them a "level mind," they lucid dream every night. They find this kind of annoying sometimes, because it means they're fully aware for the full ~8 hours they're asleep, instead of the night whooshing by like it does for normal people.
 * When they first started mutating, they assumed they were having a lucid dream.
 * Their hair is permanently blue from the Permanent Hairdye.