If memory serves, he…
- Impressed the orcs with his battle skill to the point where they referred to him as one of the few gods they venerated
- Beat Garrosh 1v1, only reason Garrosh lived is because an obstacle fell between the two
- Soloed (well, technically duo’d, since Varian was split into two people for the start of the fight) Onyxia, being the canonical reason she’s dead (you know, without game mechanics making the fight trivial)
- Singlehandedly killed a Fel Reaver (again, without game mechanics making it trivial)
There’s a bunch more, but those are a couple of highlights.