Did some offline testing with blood boil
This is what my tooltip was saying (+3 base void, ars baal, +3/20/2 circlet, +2 ammy, 2x soj, arach, magefist, 8x skillers, torch, anni, cube- so I could get another +2 skills from charm & ammy, and had 3 facets total no guardian jewel);

Honestly for PvP's sake I'm kind of happy to report the tooltip is
lyingThe blood boil radius is definitely not 22 yards, which would be ~2 screen radius (level 30 holy shock on auradin is 23.3 yards)
Instead blood boil seems to have a range comparable to nova, centered on each demon, and based on damage I'd guess only hitting each target once even if in range of multiple demons but I'd like to make sure about that
No way to test exact numbers but I'd guess actual radius of blood boil is more like ~8-10 yards. Its clearly failing to hit targets just outside of a nova-ish range from demons
Of course, you can still hit at any range with death mark -> blood boil and you're already teleporting around with 2-3 tainteds spamming fireballs for 36k+ damage (I was using consume tainted in that tooltip, but you could just go 3x, idk)