While Derik may not have noticed it, Lucien has done well to take note of this. Whenever Derik gets into a fight, as long as the enemy reaches a certain standard Derik's power seems to reduce to make the fight more interesting. But when going against stronger foes, his strength still rises to the occasion. He may not have noticed but his strength tends to level up depending on the enemy. Honestly, his power now compared to when he was taking on dragons is lower than it was at that time.
Right now, Lucien can't really say he has seen Derik getting pushed to the limit. He even suspected something was off during their trip to the underworld. He strongly believed if things turned out worse, Derik would still find a way to deal with it.
