Thinking about it this is actually a pretty good combination.
Dryads racial perks are:
- With their plant-like physique, dryads are capable of exerting great bursts of energy, whether it be strength or magecraft.
- Heal from wounds much faster than other races.
- Camouflage themselves well in woodlands.
- Can rely on just water and sunlight for emergency nourishment.
Of the two types of magic (offensive and support) support best fits Neianne. If we want raw offensive power then she already has her buster sword, which can explicitly chop through a Wyvern, so adding offensive magic isn't that helpful. Yes it does give a ranged capability Neianne is currently lacking but as a primarily melee combatant her goal should generally be closing distance not getting into ranged fights. Besides with her strength Neianne can always just throw stones if ranged attacks are needed*.
*
Something that really isn't appreciated nowadays is that thrown stones are very much a deadly weapon. To the point that stone throwers were historically used in combat because they were cheaper, easier to train, and just generally more plentiful then archers. Slings, and the various sling related weapons, were an outgrowth of this. So if Neianne has the strength to be lugging around a buster sword she has the strength to easily throw a stone hard enough to crack someone's skull open. This is actually pretty useful for assassinations since unlike bows, poison, and the like it is actually pretty hard to link a thrown stone to a particular person and they are pretty subtle to carry.
Support magic meanwhile opens up a whole host of new options for Neianne. Healing is always in demand, is literally a matter of life or death, and an area our current squad is completely lacking in. Debuffs synergize well with Neianne's natural camouflage abilities by both letting her expand upon it and by letting her stealthily cast debuffs upon her foes.
Magic is also a nice choice as Neianne's secondary 'weapon' as it covers one of the big holes her current weapon has; endurance. Neianne's buster sword lets her deal massive damage but does leave her susceptible to fatigue, especially in a prolonged battle. However as far as I'm away magic doesn't draw upon the caster's physical stamina but their magic. So when Neianne gets fatigued she can fall back and begin casting.
Of the two types I would again say that support is preferable here since after fighting Neianne is going to be wounded and fatigued which healing magic should cover. Debuffs also make withdrawing easier since they can be used to augment Neiane's stealth capabilities. Plus from what we've seen debuffs and the like are a lot less flashy then offensive magic so are less likely to draw enemies into melee combat while Neianne is recovering her stamina.
Finally on a purely aesthetic note it helps amp up the already existing dissonance of Neianne's fighting style. She is currently the small, gentle, polite girl who uses a sword as big as she is to hack people/things to death. Throw in her being a medic/support mage, something you would expect someone like Neianne to be, and it makes the shock/surprise when she pulls out her buster sword all the sweeter. It actually gets even better when you realize lots of people seem to mistake her buster sword for a shield which is something you'd expect a support character, like Neianne appears to be, to have for defense while casting.
Oh and that last point reminded that Neianne would actually be quite capable of using her buster sword as a shield while casting. Yet another reason to go the path of the mage.
