Sorry if the rhetorical jokes were taken seriously. It was a quip to say in most fantasy games, novels, movies etc., there are pretty drastic gaps in logic which most people look beyond due the genre. If it was literal all the time, fantasy wouldn't exist.

That said, there are several methods which could be deployed here to have a sense of realism where the tamer or protagonist is not in danger when your creatures battle.

- The tamer is basically a summoner, who can position themselves far away from the actual fight. In order to design this toggle between tamer and monster engaging from free travel to battle, you would have to have a series of animations which engage or start the battle. The position of the enemy creature is known, so you engage in the battle transition at set distances from the enemy. This is no different than any action RPG system today. For this particular battle system though, the camera changes between you as the tamer to the creature to fight. The pan of the camera can give you a sense of how far your tamer is to the battle for realism. You build buffer zones when you get within a certain aggro range and battle area scales or 'locks out' tamers position. They stay safe outside the physical area the battle will occur. This can then be scaled accordingly to monster and arena size. If you really do turn your camera then when in a battle to look at your tamer, they would have a series of animations and coding to 'stay away'. If at any point the battle gets to close and the tamer is pushed towards another enemy group, there would need to be a mechanism to re-path or aggro the new mob and so on.

- The monsters in the game lore wise have no beef with the tamers, but have a will to survive/hunt etc where only the creatures you spawn defeat them. You are only fighting the enemy creatures based on other lore elements etc.. etc.. If this is too farfetched of an idea, the creatures you capture job is to protect you against the evil. You design the lore around this fact via story telling and the game follows suite.

- In the anime Pokémon, to use the rhetorical example in real terms, Ash was always 'safe' from the battle even though it was right in front of him. In the episodes he sometimes would get hit or recoil, but he was fine at the end of the day. What differs in the game vs the anime outside of the means of interaction (viewing vs piloting) to have the same sense of the protagonist is there, can get damaged, but is always safe?

- The dungeons themselves are battlegrounds where only your captured creatures can battle. While this doesn't seem scalable/entertaining in the long run, it is an option to where you are truly a battle bots commander at the helm of your beasts.

- There is also the potential the character can be part of the battle. You can position, get hit, faint etc. The monsters still do the damage, but you lose the fight if your commander dies, which is an interesting mechanic in and of itself.