First, if someone says they're going to have Lutri be their companion, it's the easiest thing to fix: you just say, "Hey, did you know you can't do that?" and it likely changes what their deck is doing very little
Dark Blade + "Pitch-Dark Dragon" Each time this card inflicts Battle Damage to your opponent, you can select up to 3 Monster Cards from your opponent's Graveyard and remove them from play.
In particular, the latter has the worst compatibility with erosion infection, which can avoid card accidents, In a situation where the positions of the compatible ones are reversed
Hero of Another Story: The fate of the supporting characters when they inevitably depart Ash's company at the conclusion of each saga
If you controlled a Dinosaur when you declared Burning Sun Cavalry as an attacker or blocker, it doesn't matter whether you still control one as its ability resolves