Feels like this series is getting more shonen-y as it goes on. The earlier battles had lots of "look how cool my super cool awesome ultimate skill/attack is!" too but this is just like Standard Issue Shonen Fight #3,245b with no modifications made to it. It's pretty much copy/paste right out of the big book of shonen manga cliches. Even the fact that it's dickhead "hero" vs asshole villain.
Too bad. I liked the big in between Lloyd finding his footing with the new party and this fight. Gonna need to get back on track to hold my interest.
The attack that Grists is using is more an last resort option. I think Lloyd is buffing him now to withstand the attack.
Potions can be anything from offense to defense