Let's say that I want to use the Shadow Magic sorcerer feature Eyes of the Dark (XGtE, p. 51) to cast the darkness spell by spending 2 sorcery points. More, I would like to cast it as a bonus action, using the Metamagic option Quickened Spell.
Is this possible? Can a Shadow Magic sorcerer cast the darkness spell using sorcery points, and still apply a Metamagic option to it?
The intended final result would be that the sorcerer casts darkness as a bonus action, using 4 sorcery points and no spell slot.
Best Answer
Yes, Metamagic may be applied to spells that are cast using a class feature instead of spell slots.
The Metamagic feature says a metamagic option may be applied when the sorcerer casts a spell:
That is the only criteria: the Sorcerer must cast the spell.
Metamagic would not apply if the spell's effect were applied without being cast. For example, some potions (e.g. the potion of clairvoyance, potion of diminution, and potion of gaseous form, to name a few) say things like "gain the effect of" a spell. In such instances, no spell is actually cast, and so Metamagic could not be applied.
Then we refer to the Shadow Magic sorcerer's Eyes of the Dark feature (XGtE, p. 51):
This tells us that the Sorcerer is casting the spell. This satisfies the criteria as laid out above. As a result, the Shadow Sorcerer may cast darkness for 2 sorcery points and then apply any relevant Metamagic option of their choice for its corresponding additional sorcery point cost to that spell.
In your case, that means a quickened Eyes of the Dark darkness spell would cost 4 sorcery points (and not cost a spell slot), as you say.