Killed by a Death Sword on dungeon level 4.

[PaulBlay]

Mimics are native to deeper levels in vanilla. It is very unlikely to see one on dlvl 4.
(potion mimic dlvl 18, scroll mimic dlvl 21, ring mimic dlvl 29, chest mimic dlvl 35)

Yeah, but don't forget TinyAngband only goes to dlvl 27!

[Atarlost]

Yeah, but rings are flavored. Swords aren't. Off-hand there are four swords that aren't light-grey: executioner's sword (red), chaos blade (purple), and broken sword/dagger (dark-grey). At least in longer variants the broken types stop showing up before death swords start appearing and the fancy swords don't start showing up until much later. That means all '|' are the same color where most '=' aren't.

Both are nasy gotchas that don't belong in a game with permadeath, but death swords are worse because they're both more immediately lethal and more innocuous looking.

[Zikke]

Sounds like the recent nerf to the Death Sword's damage should solve the problem. I think it's a fun experience for a new character to get ambushed by a sword, provided it doesn't instant kill him.