HGUniversal Century

XM-X1 Crossbone Gundam X1 Custom II

The same great HGUC skeleton wearing a new skull on its chest and a small arsenal in its hands.

MechaGrade Score

3.8/5

Crossbone Gundam X1 Custom II · 1/144 · 2016

GradeHG

Scale1/144

Released2016

Runnersn/a

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The verdict

This is the well-liked HGUC Crossbone Gundam X1 engineering wearing a new coat of paint and a bigger toy box, and I think that's exactly the right call for a P-Bandai variant kit.

You're not getting a redesigned inner frame, you're getting the same double-jointed limbs and 360-degree waist that builders already praised on the original X1, plus a molded skull chest piece and a genuinely stacked weapon loadout. It's not reinventing anything, but what it reuses was already good.

Best for: Crossbone Gundam fans who already know the base X1 kit is solid and just want the Skull Heart look with more gear in the box

The full review

What it is

This kit takes the Crossbone Gundam X1 chassis and rebuilds it as the X-1 Kai Kai, the suit Tobia Arronax inherits from Kincade Nau, complete with the skull-and-crossbones chest relief that gives it the Skull Heart nickname. Bandai molded that skull detail directly into the plastic rather than leaving it to a sticker, which matters more than it sounds like on a kit this size. Assembling it feels familiar if you've built the standard X1, same limb structure, same core proportions, but the new Peacock Smasher rifle and the added melee weapons make the final pose-up feel like a different, more loaded-out suit even though the body underneath hasn't changed.

The catch

This is a P-Bandai exclusive, which means it shipped at a premium over a standard retail HG and isn't something you can just grab off a shelf, you're paying secondary market or import prices for it now. The engineering is carried over from the 2015 base kit, and that kit has a known soft spot: several builders flag a loose waist joint (some at the lower connection, some at the upper) that needs a little friction added or it won't hold dynamic poses reliably. Because so much of this release is about the new weapons and the molded chest piece, if you already own a base X1 you're partly paying to duplicate a body you have.

Who it's for

Grab this one if you're building toward a specific Crossbone Vanguard lineup and want the Skull Heart version with its own molded chest and full weapon spread rather than converting a base kit yourself, the part quality on the new tooling is worth it. Skip it if you already have the standard HGUC X1 and don't care about the extra armament, or if paying import/aftermarket prices for a P-Bandai exclusive isn't something you want to do for what is mechanically the same suit underneath. First-time Gunpla builders will do fine here since the base engineering is proven and forgiving, just budget a few minutes to snug up that waist joint.

The build story

What the build is actually like, and the engineering worth knowing about.

If you've built the standard HGUC X1 before, the assembly sequence here will feel like familiar ground, the limbs, torso, and waist go together the same way. Gate placement is typical mid-2010s HG, manageable with a sprue cutter and a little cleanup on the visible seams around the shoulders and shins. The one thing to watch for is that waist connection, it can end up looser than you'd like for holding a weapon-raised pose, and a lot of builders solve it with a dab of clear paint or tape on the joint peg rather than treating it as a defect to send back.

Where this kit earns its keep is articulation and loadout. The ball-jointed thrusters let you angle the back skirts for flight poses, the ankles handle both a pivot and a side tilt for stable footing, and the head sits on a double ball joint so you can actually tilt it up without the whole torso looking stiff. Stack that against a weapon set that includes a folding beam crossbow, a heat dagger, a scissor anchor, a screw whip, and a beam shield, and you get more posing options out of one HG than most kits at this scale offer.

Lore & trivia

01The Crossbone Gundam X-1 Kai Kai gets its Skull Heart nickname from the molded skull-and-crossbones relief on its chest, a design cue passed down from the X-3 after that suit was destroyed in the war against the Jupiter Empire.
02Kincade Nau, the Crossbone Vanguard ace who hands the X-1 Kai down to Tobia Arronax, is actually Seabook Arno from Mobile Suit Gundam F91, operating under an alias years later.
03The suit's signature new weapon, the Peacock Smasher, is a beam crossbow with nine separate beam emitters, letting it fire in a wide spread rather than a single beam.
04This kit was a Premium Bandai exclusive released in October 2016 at a list price of 2,420 yen, distinct from the standard retail HGUC X1 release.