Stalmaster

Stalmaster is a four-armed, well-armored Stalfos that can be found as a mini-boss in the Ancient Cistern in Skyward Sword. It is fought again in Sky Keep on the way to collect the Triforce of Courage, along with Cursed Bokoblins.

Strategy
Initially, the Stalmaster only uses two of its arms in combat, wielding two swords much in the fashion of a regular Stalfos in Skyward Sword. After taking a certain amount of damage, it unfolds its two other arms, which also hold weapons. The full arsenal of the Stalmaster is three swords and an axe. In this four-armed phase, the Stalmaster will generally position its swords so that it can only be struck from one direction at a time. The Stalmaster is very aggressive while in its four-armed phase, often striking with all four arms in quick succession. It has a very damaging charging attack where it first guards itself with all four weapons and then lunges forward swinging them outward. Like the regular Stalfos, the Stalmaster gradually loses portions of its ribcage as it takes damage, and when it is close to death it loses its helmet, which falls off and spawns Hearts.

Trivia

 * When the Stalmaster's helmet falls off, it can be seen that it has a third eye socket above the other two.
 * The Stalmaster's four arms wielding four weapons is similar to General Grievous, a skeleton-like cyborg from the Star Wars universe.