who is Yagrum Bagarn Divayth Fyr and The Mudcrab Merchant i cant remember
They are all from Morrowind (now that i mention it, i noticed most of these people are; i wasn't trying to do that but IMO it seems that Morrowind had more memorable characters)
Yagrum Bargarn: last living Dwarf. I don't know how long a dwarf's lifespan is (much less a disease-ridden one), but who knows. Some people are missing the point anyway, it doesn't matter if he (or anyone else) is still alive, he can be a ghost, or something else
UESP:
Tiber Septim appears to the reincarnate Nerevarine just before his reconquest of Red Mountain as an old man named Wulf, that no others can see. He gave the hero one of his own septims and gifted him with a greater power.
Divayth Fyr. He was a scientist that lived in Fyr tower. He was wearing a full suit of daedric armor (minus the helmet) and you needed him a couple times for the main quest. We've heard no word of him since Morrowind, but if anyone has discovered an immortality potion or just some way to extend their life significantly, it's him.
Mudcrab Merchant: Easter Egg. The most wealthy merchant of the game. looks like a regular mudcrab among other mudcrabs, but you can talk to him