To start with was probably my first death from age.
Orc druid finding himself swarmed by ghosts in unremarkable dungeon (most likely a nearby tension room).

Second was a promising dark elf thief who despite decent alertness and remarkable dex got hit over the head by a stone block, note that I did have the lvl 6 auto search ability and decent detect traps, life is not easy with single digit toughness (lvl 9 and max hps=35).