Need some help creating. Insane evil Half human-celestial

[KarinsDad]

A Half-Celestial can have the good type, and be evil. They retain the good type, but not the alignment.

First off, Half-Celestial do not have the good subtype. They do not overcome DR as if their weapons were good aligned.


And even if they did have the good subtype, there are two rules here that could be construed as contradicting each other (unless some type of outsider has "usually good" or "often good" in their alignment).

Alignment

This line gives the alignment that the creature is most likely to have. Every entry includes a qualifier that indicates how broadly that alignment applies to the species as a whole.


Alignment: Always lawful good

...

Alignment: Always good

etc.

and

Good Subtype: A subtype usually applied only to outsiders native to the good-aligned Outer Planes. Most creatures that have this subtype also have good alignments; however, if their alignments change, they still retain the subtype. Any effect that depends on alignment affects a creature with this subtype as if the creature has a good alignment, no matter what its alignment actually is. The creature also suffers effects according to its actual alignment. A creature with the good subtype overcomes damage reduction as if its natural weapons and any weapons it wields were good-aligned (see Damage Reduction, above).

The specific rule is that the outsiders of a given race are always a good alignment. The general rule is that outsiders whose alignment has changed still have the good subtype.

Whether or not the word "always" means "always" or "always unless the DM allows it to change (via magic or otherwise)" is up to the DM. But as written, always means always. No exceptions.

A [Good] outsider who had:

Alignment: Usually Good

could match both rules.


However, Half-Celestials do not have the [Good] subtype, hence, they do not follow that rule.

 

[Seeten]

What would you say if a Helm of Opposite Alignment were placed on the Celestial?

 

[Sound of Azure]

Don't forget, even creatures with an "always" alignment are able to change that alignment. They are just cited as "unique, or rare exceptions" in the MM Glossary, pp 305.

Your guy sounds like he would fit that bill.

As others have stated, he'd keep the [Good] Subtype even if he lost the good alignment.