Cicero's health and power level depend on what level your at when you finish the Dark Brotherhood quest. If your a level 50 when you finish (and you kept cicero alive) He becomes the most powerful initiate you can have, he's strong enough to kill an ancient dragon on his own in 3 minutes. he can kill virtually ANYONE you want him to.
ummm... -console... setlevel 81... finishes db quest... gets Cicero... setlevel 52...- okay, let's-a-go level 81 Cicero... we go kill dragons nao (i love cheating with levels, but only for like a minute to get what i want and then go back to leveling up normally... like getting the most powerful version of a weapon or a follower, then go back to the level i earned with my own effort, i also made Delphine non-essential, but that was for my own personal amusement and shouting her outta the temple was for science... the experiment was to see if i would laugh after doing that... it was a success)
make sure to get him good light armor, and (if you can) get him a forsworn sword along with with an imperial sword. If you do he uses both of them (imperial for first hand, forsworn for the secondary hand if I remember right) He's even more impressive with two weapons
I love cicero X3 I travel with him everywhere... partly because he kills all the ancient dragons for me XD but I've traveled with him for so long that when we enter a city I know what he's gonna say and when he's going to say it there's a pattern
These Dark Initiates level with you up to 81, when Cicero will be stuck to 50
Ill walk with da powerfull =3
They aren't as funny as Cicero, thought (expect when you'd like to travel in peace)