Right. He's not lying in that statement. He literally was granted powers and he was actually able to accomplish those feats. That's how he became the Blade of Frontiers. The lie is just that he didn't train to become so great, and lacks the actual hero spirit behind them.
I think the abilities pushed him to become this, but his fine tuning is his own. He obviously trained with a sword/combat. And I believe even Astarion will comment on how strong and fast he is, which doesn't really come from the abilities. He has most of these scars I would assume due to fighting these beast upclose. And when you first see him, the first thing he does is jump straight to a goblin rather than blast them.
