While raging, a Barbarian cannot cast spells.
The Way of the Sun Soul monk's level 3 feature, Radiant Sun Bolt (Sword Coast Adventurer's Guide, p. 131), enables to make ranged spell attacks.
Can a multiclassed barbarian/Sun Soul monk make the ranged spell attack from the Radiant Sun Bolt feature while raging? Or is the Radiant Sun Bolt feature considered a spell, and therefore unusable by a multiclassed Barbarian Sun Soul Monk when raging?
Best Answer
I'm assuming that you're asking whether a barbarian that multiclassed into monk can use the monk subclass feature Radiant Sun Bolt (XGtE p. 35). (Or a monk that multiclassed into barbarian - same thing.)
If that is your question, then the answer is yes.
Rage (PHB p. 48) states the following about spells:
The Sun Soul monk's class feature Radiant Sun Bolt states the following:
This ability explicitly uses one of the attacks you gain from using the Attack action. Therefore, you are not taking the Cast A Spell action (PHB, p. 192), and you are therefore able to use the class feature during your rage.
However, your DM could rule differently due to lore reasons.
The description of the Way of the Sun Soul monastic tradition states (emphasis mine):
That sounds like it would be difficult to do while raging. Hence, it's within reason to rule this out, but since you could easily find an explanation why it is possible while raging (i.e. you trained doing it for so long, using it comes naturally), your DM should definitely tell you about his house rule before you choose the subclass or even start multiclassing into monk/barbarian at all.