

If you need to “cheat” (e.g. fudging a roll because you made your monster way too powerful) then never tell the players, it will only ruin their sense of immersion.
Try to do voices, players love them even if they’re shit and it helps distinguish the NPCs. The voices don’t have to be remotely good and you don’t need to be good at accents, just try things like “gruff voice” for the grizzled mercenary or “weirdly enthusiastic” for the mad old wizard.
Guess those potions were to strong for him