In don't play DND so not familiar with the Lore. But given the understanding Shar is evil...does playing her as a light Cleric really break that immersion? Doesn't seem like much of a stretch that A Cleric with an Evil God would want to be caster heavy and blow up things with Fireballs.
Shar is the goddess of Darkness. She wants to destroy all of creation, because Selûne create the Sun to warm Chauntea.
The Light domain is about Light and Warmth.
Basically, a Light Cleric will *always* be in total opposition to Shar, thus it would break immersion.
Kinda like making a War Cleric of Eldath (Domain: Pacifism).
