So...
How's everything coming along?
Posted merely because I came up with an idea for a cape and I think it would be interesting for inspiration if nothing else. Blood-based powers, or bodily fluid based; in which case it would relate to the four humors. In the case of just blood, they could easily be named Sanguine or Crimson or Scarlet or something. Humor based, not so sure.
Blood, Sanguinity, is associated with Fire and would probably be the main power because it's the most accessible the most easily in the largest quantities, as well as Fire typically being thought of as the Combat element. Whether he's just making his blood effectively explode, or causing it to create constructs from it as it multiplied or flowed freely, he would grow stronger the more of his blood was spilled, in this respect, and a side-effect would probably be the capacity to regenerate blood at an amazing rate. By which I mean he could cut his own throat as a last resort for more power and come away dizzy(if he survived the fight itself), but very much alive.
Saliva, Phlegma, is associated with Water and would the second most accessible power, though it would likely require much more preparation, and possibly grow weaker the later into a fight he was, being the counter of Fire and Sanguinity. Not too much of an idea for what powers he might have, though being able to flash freeze things he basically spat on would be interesting. Side effects would probably include a highly-active salivary gland and a much stronger spit reaction(you know how sometimes if you move your tongue weird a jet of spit comes out? That thing's on steroids).
Yellow and Black Bile would be more difficult to access, and more abstract in effect and influence, likely based on mood more; Choler is associated with aggression, anger, and Air, while Melancholer is associated with depression, sadness, and earth. Unless he vomited on someone (which isn't something I think is really a viable tactic, superpowered puke or not), he couldn't really directly affect them with these, but the amount of Choler present could increase his speed and reaction time, while Melancholer might make him more typically stronger and durable.
I came up with the blood guy first but thought the Humors thing might be interesting too.