what is Nero's sexuality?

Does he practice any form of arts, crafts, or creative hobbies? If so, what and why?

You've mentioned that he suffers from insomnia and some of the ways he tries to deal with it, but on nights when nothing is working, what does he do to fill the time until "day" comes again?

Let’s call him a bisexual with a piquant taste.

He is a heterosexual when we talk about human beings. The human male is out of his sexual interest. He can flirt and solicit a man, grab him, touch him everywhere, imitate a sexual act, but he has no intention of actually sleeping with him, just making him feel uncomfortable and vulnerable. For Nero, it’s just a form of assault, intimidation and manipulation that he uses when he needs to show his dominance over someone.
He is usually more gentle with women. He is only attracted to voidborns or just pale, skinny ladies, if we are talking about real love, not just one-night intercourse.
Nero is a xenophile as well. He is attracted to Eldar’s body, and generally considers them to be perfect creatures. Tall, thin, pale, graceful and strong. He liked Urliet, for instance, but Nero respected her boundaries, giving her time to grieve and adjust to new surroundings. Eventually, he lost interest to her after meeting Marazhai. He did not plan to sleep with him, it just happened. He wanted to be friends with a Drukhari who could understand Low Gothic. But what happened is what happened, and now he is bisexual with xenos.
He’d probably sleep with a sslyth too.

Nero likes to dance. He learnt it when he was younger and it became his favorite way of expressing himself through his body. Nero’s walk sometimes looks like the dance movements.

There are many ways to fill the sleepless hours, such as inviting Kibellah or Marazhai into his chamber. After Marazhai’s “feast”, Nero is likely to faint.

When Nero is not in the mood to mutilate his body, he reads books about the Warp and xenos in his chamber. He annoys Heinrix by coming to his room, or Nero chooses the Interrogator’s room to read sitting on his bed.

He may consider walking around the voidship, having a small talk with Ravor, looking at the stars alone and smoking, or having his subordinates entertain him.

Thank you, Mird, love your questions 🖤