|Valentine's Ike is undoubtedly among the strongest red armor units in the game due to his powercreeped Aether (Radiant Aether), glaringly high speeds for an armored unit, and astounding base kit. This build focuses on maximizing the potential of V!Ike's Special.
The IVs should be +Res/-HP. A bulkier Ike (especially one with a mixed bulk) will be able to heal back damage taken much easily. This build strays away from +Atk (a common IV) because a more powerful first attack will lessen the healing potential of Radiant Aether.
Wo Dao+ (Res) is the weapon of choice, due to its magnification of Radiant Aether's damage and, therefore, healing power.
Fort. Def/Res, although rare and also without DC, is valuable to use here because V!Ike is in desperate need of tankier stats to pair with his healing special. The attack penalty, compared to standard Fortress skills, is quite small (and may actually help with lowering the damage of the first attack, thereby increasing the healing potential of the special).
Special Fighter, which is part of V!Ike's base kit, is vital to his performance as an armor unit. Faster special charging on both phases means that he can heal up more often.
The C slot is quite flexible. If V!Ike has armored allies, Armor March could be useful for added mobility (this soft counters ranged units, which are this build's #1 counter). However, since V!Ike needs more speed to double reliably, then if there is a lack of support, V!Ike's innate Even Spd Wave will not disappoint.
The S slot is mildly flexible. Fortress Res enhances mixed bulk, which pairs well with healing specials. However, if no one on V!Ike's team (including V!Ike) has armor march, Armored Boots will suffice. Armored Boots has great synergy with Radiant Aether as the special will help meet Armored Boot's 100% HP requirement.