The Septim Dynasty had many colorful characters throughout lore and the series, and their influence managed to show up even after it ended with the turning of the age.

Pelagius was TES' Caligula except without the constant orgies, violent tendencies and was more insane. Out of all of them I think Pelagius is the most interesting and special.

tough one...

for me its a Three way tie..



Tiber Septim became part of the Oversoul of Talos, so he is an obvious choice..

Then we have Pelagius The Mad, who is just a really fun character to read about.

and lastly we have Martin. The Illegitimate Son on the Emperor, raised by a farmer. was a Sanguine Worshiper before becoming a Priest of Akatosh. being able to use the Knowledge he acquired as a Sanguine Worshiper to translate the Mysterium Xarxes and Open up a portal to Gaiar Alata, and ended up sacrificing himself to summon the Avatar of Akatosh, making the Dragonfires obsolete....