An experimental weapon developed by the Tenba Conglomerate, this massive robotic tank is stronger than the A.B.R.α that served as the first true boss in the game, and it's also the first boss that can make use of Stored Attacks. Krusche temporarily joins in during this battle so make sure to use her abilities the best possible.
The Ikaruga Mk. I has a total of three attacks: the 70M Vulcan, which deals physical damage to a single target, the Four Chambered Missile, which deals physical and Fire-elemental damage to all your vanguards, and finally, a Lv. 1 Stored Attack called Death Hover, in which he floats briefly in the air to then fall and attempt to crush your Reyvateil. Its stats are relatively high, but it has an extreme weakness to Song Magic, particularly to Wind-elemental attacks, so try to play that to your advantage, while trying to raise your Harmonics levels to the max before finishing it off.