How I imagine this fight to go.

Continuous ground focused energy field, basically how things ran in King Behemoth. Progressively becoming stronger as the fight goes if certain things aren't handled properly, from a small tick that is mostly negligible to a hard tick that can wipe a party within moments as healers just cant keep up with it.

Like the Slyphs, he won't actually be on the ground, he'll hover, possibly even moving rapidly across the arena quickly. I'm guessing teleporting, without having a set tank position such as how Ifrit jumps but returns to the original tanked location every time.

I doubt we'll see the raw, forceful way that the other Primals are. I imagine his fight will almost be more like Garuda in nature.

Ifrit is explosive, charging you down. Garuda tries to cut you down, sending out multiple foes to attack from multiple angles, calling on copies/the sisters to distract you, stretch you thin while building up for a big hit. Titan is like his element, forceful, but grinding, trying to crush you the entire time (tumults/geocrush), Leviathan is like Ifrit, using his element against you, rocking the boat, careening across the platform to try to plow you down. The biggest glaring issue in Levi Ex is he's trying to drown you. Ifrit wants to burn you. Garuda wants to cut you down and Titan is trying to crush you. So I see Ramuh wanting to make you stop, paralyze (as someone else mentioned) and gradually destroy you. But I see the tempo of his fight being slower than the others, which is where the electrified field comes in, moving around the arena to deal with the party at multiple angles, trying to exploit weakness in formation.

I hope, I won't be disappointed, he's among my favorite 'summons' in the series. Right next to Alexander.