NOTE: I will post the builds at a later time. for now, I have stats and a long description.
Siegbert: Future King
Siegbert has managed to extract himself from his Father's shadow and stand on his own 4 legs, trading away the defensive, Distant Counter Siegfriedfor an offensive, Swift Sparrow 2 Dark Greatsword. Compared to his father Xander has slightly lower defense and Resistance, and significantly reduced health, but slightly increases his Attack and shoots his speed through the roof, being the fastest cavalier to date.
His massive power lets him break through and kill nearly every Red unit lacking Wary Fighter, whereas a special proc from Draconic Aura or Dragon Fang let him bust through a significant portion of blue units. With Swift Sparrow 2 in his A slot, he reaches 58/43 Atk/Spd offenses at neutral, allowing him to double any unit with less than 38 base speed. Most importantly however, he is mounted, capable of initating with the range of an infantry mage/archer to improve his offensive niche, and grabbing Hone Cavalry for a mind-blowing 64/49 initiation offense, allowing him to kill just about anyone who isn't wielding Swordbreaker/Wary Fighter, or an incredibly bulky blue.
He pays for it however with painfully mediocre HP for a melee unit, and an utterly destructive resistance stat, with only Fredrick's 14 losing to his 15. His mediocre health may let him easily activate Desperation, but his awful Res results in a magic user needing a mere 34 magic to 2HKO him, or 43 for Green mages, a stat every single optimized magic tome reaches. This makes it dangerous for him to rest in the range of any Blade-Tome user when in Desperation range, and the range of Blue Mages, Blue and even Red Dragons are simply off limits to him at all times as he can never reliably take hits from any of them except an unbuffed Blarblade Odin, and he cannot kill either Adult nor Young Tiki on initiation without dying to Quick Riposte.
Siegbert is only summonable at 5-stars. However, he has a boosted BST that brings his stats to the level of a lower-BST Infantry unit. Similarly to Sigurd, this gives him a boost in Arena, as he has both that and an exclusive weapon to boost his weighting to that of any usual legendary infantry such as Lucina or Seliph.
Builds (Heavily WIP)
Bold = Reccomended for build
Italics = Distinctly Suboptimal yet possible for build
Underlined Bold = Necessary for build
Desperate Move (General Offense)
Usage: General-Use, Deadly Initiator (Aim to initiate combat, risking life for more likely kills), Endurance(Becomes significantly more capable of killing as time goes on)
Our Other Boy (Galeforce Offense)
Usage: Arena Offense(Excelling either at point score or at killing meta units) , Safe Initiator (Aim to initiate combat, surviving the fallout almost assuredly alive),
Penny Pincher (Budget Offense)
Usage: Extremely Cheap (3-4* inherits only, <= 3 inherited units) Deadly Initiator (Aim to initiate combat, risking life for more likely kills)