Gotta admit, got this guide off of a Youtube uploader, can't remember his name. Super fun build that allows decisive jump-in moments to kill, not to mention with Illidan's already mobile kit, the ability to get out of a fight as well. While first aid allows for some much needed sustain, considering his base kit doesn't allow for much health regen. Blood for Blood creates the opportunities to really secure a kill or sustain yourself through a fight, while having the global ult is just pure fun, but if timed right and in the right location, can really be a game changer.