My money goes on The Covenant. Ships in Halo could obliterate any Mass Effect ship (save for Reapers) effortlessly.

But Protheans have particle beam weaponry that recharges on it's own indefinitely.





RECHARGEABLE FUCKING LASERS.

Small arms.

Small arms which can't do shit in a space battle. The most the Protheans could do would be wage a guerilla war on the ground. In the space battles, they'd be crushed.

No no no! Just think about it. There's an army of a million Protheans on the ground with these assualt rifles. This isn't even counting their heavy weaponry and other stuff. The Reapers took hundreds of years to wipe them out, because even through they were crushed in space early on, they were adaptable. We don't really know what the Protheans had, but in the MEverse, they were leagues ahead of any current cycle for technology. Anywho, back to the point.

I want you to imagine, a million of these rifles aimed at a target. These rifles, when firing, overcharge into a stronger beam. I'd wager that if a million of these rifles were aimed at a low orbiting Covenant ship they might stand a chance at punching a hole through it's shields.

Any Covenant on the ground would get shreked by them.

But Protheans have particle beam weaponry that recharges on it's own indefinitely.





RECHARGEABLE FUCKING LASERS.

"Fucking lasers"? I've seen enough hentai to know where this is going...

I can see your point. But the Covenant could just do a few strafing attacks with some of their stealth aircraft and wipe out the Prothean ground forces. Then deploy infantry to mop up the rest. And the ships in Halo are honestly overpowered, period. One of those Covenant Assault Carriers is 5 times the size of a Reaper dreadnought, and could probably win in a 1v1 duel against it. The Covenant is a significantly stronger force than the Reapers. All the Reapers would have against the Covenant is their indoctrination.

OP just said no orbital bombardment. Although the space tech of ME is low compared to Halo's there's no doubt that the Protheans ore tough ground fighters. They were high tier compared to the other cycles, and the Reapers were above them, and they managed to hold out for hundreds of years against indoctrination and starships that could just bomb them from orbit.

If this was a ground engagement, I think the Covenant would lose in a war of attrition. As well as the powerful tech they have which could easily contend with covenant small arms weaponry, Protheans were Biotics as well. This would be a LOOOOOOOONG fight.