[the REAL Minos Prime]

Shine Sword is mostly a gimmick weapon. Extra damage and a transformation. I more often see people take Shine Sword just for the transformation, not intending to actually use it as a weapon.

To encourage its use as a weapon, and cement its role as a paladin's weapon, I propose a simple buff - 


Shine Sword can be used to cast Mercalan domain spells.


If this is considered to be too overpowered, then I'd add the caveat that the user must also be under the effects of Pray in order to cast with it, to further lean into the Paladin style of a religious knight whilst also not slinging Shine Rays and Malmelos left and right. However, I don't see why it being able to cast Mercalan at all times would be op, given that it's both an 8-Star and a black book weapon. A weapon that requires either a really lucky drop or a special recipe should have some special quirks that make it stand out.

[Raigen.Convict]

Yes please, give me shine knight paladins who smite

[Snake]

It's actually fine if it does cast mercalan spells, actually.

[polly]

It's a FAI weapon. It has a holy theme, and it literally gives you +2 FAI (along side +2 WIL).

While it's transformation is solid on it's own, I don't see a reason as to why it can't cast Mercalan spells. I don't think it would be overtuned.

I'm not saying every FAI scaling weapon should be Mercalan casting tools, but I fail to see why Shine Sword isn't one.

[Poruku]

The issue with shine sword is that it wants you to build faith. The only faith builds that make any sense are spellcasters that use healing. Thus, this weapon doesn't fit in the game in its current state, so I'd say it'd make sense to make it a mercalan casting tool.