In Death's Door, the umbrella is a low-powered joke weapon, but the game encourages you to use it exclusively. 

Here are some suggestions.

The player character and the grey crow and umbrella achievements standing in front of the death gate.

Deathgate is another game that lets players choose their weapons as they battle evil undead and giant spirits.

 Among the five weapons at your disposal is an umbrella.

 It has a very low damage output (half that of the starting sword) and is generally considered a meme weapon.

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However, both the Deathgate community and developers support it, and many have tried to complete a run using only this poor weapon. 

If you're one of those people, here are some tips for beating the boss and getting through the tough time honestly.