Well, rainbow drinkers make ridiculous ammount of sense, really. Troll biology let's some shoot laser beans that defy physics and there's"i can talk to dead bf" trolls. So it's not weird that they can come back to life after (at least clinical) death. Shining? They are in cavers. Light makes it easier to see in pitch black places + can scare/stunn predators. Also, jades are not common so it's good when they can stay kicking. Blood drinking? Many grubs/young trolls die. One shall not be wasteful.

Yep, pretty much, although I should point out I wouldn’t say the coming back to life to be part of the Rainbowdrinker process 100% sure. It may be, however, Kanaya is a Sylph. Sylphs and Maids, the Creation pair, are the characters that have consistently brought themselves back from the dead. Aranea with the Ring, Kanaya’s Rainbowdrinkerism, Aradia’s Prototyping and God Tier Ascension, Jane self-resurrecting after getting stabbed, it’s like. Their thing.