What is the damage of end crystals to players?

The explosion strength is 6, the same as a charged creeper, and I believe that damage per explosion strength is constant, not variable between the source of the explosion, so it should be 97 damage at 100% strength, so with armor that has 96% absorption, you should take 3.88 damage or 1.94 hearts. As for how many, with ten hearts, it will take five or six crystals as an estimation, probably five due to the rounding up or down of damage, but it could take six in total, just with you being extremely one-tap after the fifth.

The maximum damage on hardest difficulty given the end crystal's strength, comparable to a charged creeper is 127.5. 4% of 85 (100%-96% is 4%) is 2 1/2 hearts (rounding). Big_Chungus is correct damage from explosions is consistent, provided that a variety of variables are not changed. It would take 4 crystals to kill a player with maximum damage reduction.