All Your Base Are Belong to Us: Quite literally with the 'Eminent Domain' mutation.

note Given that 'Chain of Ascension' revealed some of the Tal'darim stayed loyal to Amon after Alarak became Highlord, you could Hand Wave that they're among his forces as Dark Templar, Void Rays, etc., and stole the Purifier technology for him. But if the AI was limited to just the unit compositions featured in the campaign, they would have limited options and gameplay would quickly get stale.

Provided it's in their AI script, Amon's forces are capable of using all units of all three races, not just the ones his forces had in the Legacy of the Void campaign, including not just units based on Purifier technology that were created by Karax during the campaign, but also Nerazim units like Dark Templar and Void Rays, when it was a major plot point that Amon couldn't control the Nerazim.

The enemies in 'Malwarfare' are Hard Light holograms, but they still drop biomass for Abathur and essence for Dehaka to prevent these commanders from being denied their core mechanics.

If you're looking to fully max-out your co-op profile, that's 2,080 levels in all, Mastery and Ascension included, so get busy.

Patch 5.0 introduced Prestiges, which add a further 45 levels to each commander.

Then Patch 3.17 dropped, bumping the level cap up to 1,000, so players at maximum Mastery will have another 910 Ascension levels to go.

Absurdly High Level Cap: The initial level cap was indeed high (90 Mastery levels, on top of the 15 needed for any given commander), but nowhere near ridiculous.

Players can still use the paid commanders but their level caps at five, limiting how effective they can be until purchased. The base commanders - Raynor, Kerrigan, and Artanis - are free to all players, while other commands must be purchased or come bundled with other Starcraft II items, depending on which commander and the time in question. This includes the addition of weekly 'mutators', missions where the maps are given new quirks, like temporal fields that slow time randomly appearing, or enemies that grow stronger as their allies die.

Since its release with Legacy of the Void, it has continued to be supported with balance updates, new gameplay features, and new maps and commanders. Intended as a way to keep players interested in the single-player campaign coming back to the game for new challenges beyond transitioning to melee play, Co-op Mode unexpectedly became a Breakout Character in terms of gameplay - according to a developer in November 2019, it is the most widely played game mode of Starcraft II.

Starcraft melee vs free for all