|With Morgan's amazing default kit, this build aims to utilize Morgan's strengths without having to sacrifice major 5-star units.
Weapon: Grima's Truth is one of the best support weapons in the game, with a good 14 MT. It acts as a built in Atk Smoke 2 and Spd Smoke 2, as well as Seal Atk/Spd 2 in one. It also has the added benefit of giving all allies within 2 spaces +Atk/Spd 5, which is better than Hone Atk 3/ Hone Spd 3. This gives Morgan a good niche to fill as a support mage. Grima's Truth comes in default with Morgan.
Assist: Reposition is always a solid choice for Morgan, like many other units. It allows Morgan to move allies out of harm or into combat. However, if you want Morgan to play as a buffer, Rally Def/Res will work, as Grima's Truth can always be used to proc Atk/Spd. You can find Reposition on Selena and Barst, and Rally Def/Res on Roderick.
Special: Dragon Fang comes in default with Morgan's kit, meaning that there is no skill inheritance needed for it. Dragon Fang, when proc'd, gives Morgan a +50% to his total damage. As morgan will be hitting enemies to debuff enemies and buff allies, the extra bit of damage helps. If you want something a bit faster, Luna will serve you well, which can be found on units like Catria and Frederick.
A Passive: Death Blow 3 will fall into Morgan's A Passive, as it gives him a needed +6 to his atk. If you don't have a Klein to sacrifice,
Darting Blow 3 also works, which is much easier to find on units like Florina and Rebecca. If you want more survivability, Fury 3 will work wonders for Morgan, as his defenses are very low. You can find Fury on Hinata.
B Passive: Dull Ranged 3 is Morgan's fodder skill, as (currently), he is the only unit to have it. It's effect is the same as most of the Love Abounds! units, where it shuts down all field buffs from ranged threats. This gives him an advantage over mages and archers, especially green meta threats like Nino and PA Inigo. Of course, he naturally comes with this amazing skill.
C Passive: Spur Def/Res 2 comes naturally with Morgan, so it is a no-given that he should use it here to cover for his lack of buffs in the defensive areas, however other buffs can be put here to suit your needs. Morgan's default C passive is conveneint for those who want to use him right off the bat.
Sacred Seal:Morgan's Sacred Seal is very flexible, as he can not maximize ploys that well, and he won't be able to get much out of heavy/flashing blade. It all comes down to what you need Morgan to do. Breath of Life 3 and Savage Blow 3 can be used to make Morgan as a hard-hitting support, while spurs, fortifies, and drives can be used to cement Morgan as a complete buffer.
--Cheers from Xerneis!