The ender dragon is a giant flying hostile boss mob found when first entering the End. She is the largest naturally spawning mob in the game. She guards access to the end gateways that provide entry to the outer end islands in addition to the exit portal that allows return to the Overworld as well as access to the end credits of Minecraft. Because of this, she is known by most Minecraft fans as the 'final boss' of the game. Her attacks involve charging at the player and her unique dragon acid attacks. it has 100 hearts of health, deals 1 and 1/2 more damage depending on game mode starting with 1 and 1/2. drops nothing but you can get the dragon egg after.
Wither
The wither is a player-constructed and highly destructive undead hostile boss mob that can hover in mid-air and fire barrages of explosive wither skulls at its target (which happens to be everything living). It is the only source of nether stars, which are used to craft beacons. The wither is spawned by placing 4 blocks of soul sand and/or soul soil in a T shape and putting 3 wither skeleton skulls on top of the three upper blocks. The last block placed must be one of the three skulls and can be placed by the player or a dispenser. Air blocks are required on either side of the base soul sand or soul soil under the upper blocks (non-solid blocks such as grass and flowers prevent the wither from spawning). The building pattern can have any orientation (including horizontal and upside-down) as well as the skulls; the wither always spawns at the foot of the pattern. When the wither has successfully spawned, it is angered and creates an explosion around itself. it has 150 hearts of health, deals 2 and 1/2 hearts of health of easy mode, 4 hearts of damage on normal and 6 hearts in hard.
Warden
Warden is an extremely powerful hostile mob summoned by sculk shriekers in the deep dark biome. It attacks by swinging its arms downward, dealing the strongest melee damage of all mobs, and can also release a sonic boom attack that immediately strikes the target, piercing through obstacles and deals damage that cannot be reduced except by the Resistance effect. Wardens are completely blind and rely on vibrations, smell, and touch to detect players and mobs, and can therefore be evaded via sneaking, diversions (snowballs, arrows, etc.) and wool. it has 250 hearts of health, deals 8 hearts in easy, 15 hearts in normal, and 22 and 1/2 hearts in hard. it drops a single sculk catalyst apon death.