Minecraft Legends

EDIT: Thanks to Jondonkey tC for mentioning that if you miss killing the beast, he will attack again another night with the same health he was left at, I missed this in my initial playthrough.

Bosses in Minecraft Legends spawn after destroying all of a factions main bases.

The Beast is the Boss of the Horde faction. Usually a final base will appear for you to destroy with the boss of that base aiding in its defense such as the Devourer.

The Beast behaves slightly differently however - once you have destroyed the 3 main bases of the Horde you will need to wait for the beast to attack one of your villages and you must defend it as you would a regular base defence.

There is one significant difference however, the Beast will spawn and attack your base and you must defeat him BEFORE the invasion timer is up. Failing to kill the Beast in time will result in the victory cutscene playing however you will NOT get the achievement. If this happens quit and load the game again and the beast should target one of your bases again the next night and should continue to do so until you beat him within the time limit.

Ensure you are well stocked on every material, especially coal it will be worth having at least 2 coal gather structures built.

As for strategy here's what I personally did 3 key things:

1) Surrounded my base with 2 sets of walls with archer towers in between the gaps, all within range of a mason to upgrade the walls and towers to stone. (The beast can sprint though walls but the wall's main function is to keep other piglins out so you don't need to worry about your base health) and all in range of a home to heal all my structures.

2) Use Creepers and skeletons for your army, sending a full wave of creepers at the beast when hes resting from his charge takes massive amounts off of his health bar and the skeletons are great support as well complete both of their homestead missions to be able to summon them in the heat of battle. (it may also be worth upgrading how many mobs you can rally/create, my army had 34 slots)

3) Confuse the AI with a brilliant trick - place 1 column walls and dot them around your second outer wall this will distract enemies that prioritize taking down walls such as the hoglins and your towers should kill them relatively quickly whilst they are distracted.

Once you defeat the Beast within the time limit your achievement should pop.

If you're playing on Legendary and are struggling with this boss rushing through your walls and killing the village pretty quickly you can actually glitch it out by placing archer towers on top of trees/rocks and then mining the resources underneath so that they are floating. This causes the Beast to just sit under the archer towers confused while your army kills him.

Check out this video for a demonstration:

https://imgur.com/a/WRsupBc

Found this boss to be frustrating compared to the other two so hope this helps!