It's a fantasy role-playing game.

DM: You are Tiberius Stormwind, a dragonborn sorcerer . You are the member of the famous group of adventurers. Previously, Hotis then attempts to flee but is held back by you. As the team assault him, a suit of armor animates and comes to his aid, hitting them all with a stored Fireball.
DM: It also slowly repairs itself over time. So yes. You cast Slow. The rakshasa appears unaffected. However, the guardian's movements do seem to shimmer and shake as it's forcing its way through the arcane net you've now cast around it.
Player: Cool. So now it takes a negative two penalty to its AC and its dexterity saving throws, and it can't use reactions.
DM: Yep.
Player: Sweet. And I move as far away from everything as I can.
DM: Okay. So where are you going? Over here? That's about as far as you can get away from everything.
Player: That's what I do.
DM: All righty. That brings us to Thorbir.
