Walker

A walker is a Herobrine like creature with 25 hit points, or 12.5 hearts. They are able to carry swords (all vanilla materials), Bigswords, healing staffs, hookshots (to pull you in with), spears, bows, splash potions, and shields (with swords). They can be equipped with armor ranging from chainmail to diamond. Walkers can be found in Limbo, Castle dungeons, and Underwater dungeons. These castle dungeons are to this day very often found in snowy areas, and are made of a small village that leads to the castle. A similar NPC found in Hexxit is the Pirate mob.

Spawning

Walkers are spawned from spawners that resemble vanilla dungeon spawners but without the fire or spinning mob model. Each spawner only spawns one individual Walker, and once that Walker is spawned, the spawner will be destroyed. Walkers will spawn on Peaceful, so be careful.

Walker spawner found on top of castle.

Types of Walkers

There are several types of Walker:

Regular walkers that carry swords (armor and weapons range from chainmail to diamond)
Archer walkers that carry bows (be careful because these walkers do a lot of damage and have a relatively fast fire rate)
Defender walkers that carry swords and shields (these can take a lot of damage, so use a Poison Staff if you have one)
The Walker Boss carries an ender sword and a shield, and he has a cape on his back. (This will most likely be the last walker you fight as you work your way up the castle/tower/dungeon.) He is very powerful with 250 hit points, and he has several attacks ranging from melée sword swinging to ranged arrow attacks to magic whirlwind attacks. As he takes damage, his armor will start to break off, allowing you to gradually do more damage to him. When he dies, he drops his sword and a diamond block with a rare chance of dropping a nether quartz shield.
Healer walkers walk around with a Staff of Life and will heal themselves and any injured walker near them for one hp about every 0.25-0.5 of a second. Make sure that you take out these walkers first as they will heal any walker that you did not kill fast enough.
Bomb Walkers throw bombs at you from a distance. The bombs are very similar to Ghast fireballs, being that they have the same skin. These bombs will explode on contact, setting fire in a small radius around the explosion, but they can be deflected with a sword. For fighting these, try and single them out and hit their fireballs back at them, then get in close for the kill.
Infernal Mobs can cause you great grief and strife. Be very careful near these guys especially in a group.
Ninja Walkers are quick and powerful with a dagger be sure that they don't live long
Flag Walkers: This variety of walker appears infrequently in walker castles. It holds a large flag in its hands, enabling it to buff its companions in battle.

This is the "Citadel" walker castle

inside of the Citidel

The largest walker castle which i like to call "The marketplace"

The marketplace inside of the castle

The "single tower" walker castle

Finally my favorite castle "The Mountain Fortress" (The Eyrie)

Back picture of the mountain fortress

the village under the fortress

the small village at the top of the mountain

The "sky cells" which if you're not careful you could get locked in and trust me it's a LOOOOOOOOOOOOG way down

Castles

The castles that the walkers inhabit spawn naturally and have large rooms and plenty of space that is needed when running heavily modded games such as Hexxit. There are also chests in many of the rooms that have food, rare enchanted weapons and armor, essences (wind, fire, dark, ice, water, etc.), and valuables (diamonds, emerald, gold, lapis, etc.) Raiding battle towers can also help you in conquering these castles because the chests in the battle towers have rare items and plenty of diamonds. Below is a castle that a player has taken residence in.