Monk

Muscular Monks are here to destroy armored units. They will kick several times enemies as an attack, which seems to work out fine against armor for some reason.

Computer
Monks can be used to clear any armored units with ease (even Cavalry), except of course Dread Lord and High Lord (for obvious reasons). This is due to armored units nearly all being effective against other armored units only, meaning light Monks won't take too much damage. Swarms of Ninja can stop small groups, but Mages are perfect for countering large swarms.

Mobile
Monks are still a great counter to armored units, but they won't be as effective as in the computer version. This is in part due to more units actually dealing damage to Light units. Notably, Archers can clear groups of Monks before they even enter combat. Some players buy Blade Guard as a stronger replacement, but most will simply keep Mage as their Tier 2 Light anti-armored unit.

Trivia

 * The design is very similar to some fighting game characters such as Fei Long from Street Fighter and/or Marshall Law from Tekken.