She's Dead, but we learn that chosen one are somewhat the reincarnation of dead players, and Tiera is the one that inherited marino's power, but with her statue a priestess marino wasn't completly absorbed and part of her spirit still lingers inside tiera, untill she meet shin again at one point and completely transfer her power over to tiera
@REDS The idea was all players were trapped in the game, SAO-style. First chapter Shin beats the final boss and 'unlocks' the log out for everyone. Guessing they didn't know what happened to players in the real world after dying ingame.
Marino was terminal ill, she died due to it becoming much worse when someone wanted to kill her inside the death game. we will later meet a semi pker with the same problem.