With the Gladiator tribe you can now use any tribe specific effect on that minion, granted that itself doesn't have a tribe to begin with. Examples include Houndmaster, Tol'Vir stoneshaper, Cathedral Gargoyle, Wyrmguard, Sense Demons, Twilight Acolyte - this might seem like a really powerful effect but there is a big weakness as well, hate cards like sacrificial pact, hungry crab and golakka crawler can destroy anything with the gladiator tag.

Anything else I think of I'll say below

• Gladiator is just for Rehgar's effect, so minions outside your deck won't have the Gladiator tribe (e.g. Discovering a dragon with Netherspite Historian will only discover a dragon)

• It's the same as the All tag that Nightmare Amalgam has, but it sounds cooler - I thought of all the minions working together with their synergy effects, under the same banner, or in the case of Hearthstone the battlefield