A Golem is a large construct. Typically made of a tough material, like stone or metal, it's a rampaging, relentless monster on the battlefield, stomping away at its enemies until all are dead.
Golems are constructed from the overall theme and elements of the Realm it appears in. However, every Golem fights the same, with powerful physical slams. Luring a Golem onto a damage tile, such as spike traps and fireplaces, is a particularly effective tactic. Turbo Attacks are very effective against Golems.
With more Realms available, more Golem types are available. Now, however, they will shield themselves if they see a powerful attack coming, such as a Turbo Attack or the last hit or two of a combo. Defeating a Golem nearly always results in an item drop, much like a General.