Obelisks are completely impassable (even after destruction) and give no terrain stars. They cover nine squares, in a 3x3 square. They have one spot that can be attacked - the door at the front of the Obelisk. This weak point has similar defences to a Medium Tank. Black Hole units within two spaces of the Obelisk get 2HP restored, along with their fuel and ammo, for free. Along with the Black Crystals, they are the only way to repair an Oozium.
They act as the main source of Black Hole's power in Dual Strike and were invented by Lash for the Bolt Guard's campaign in Omega Land. They produced massive amounts of energy and materials, but turned the surrounding area into desert and wasteland. They appear twice in the Campaign mode, and are the main objective in both maps they appear on.
First, one appears in Crystal Calamity. This Obelisk is protected by a barrier generated by the Black Onyx, as well as a Black Cannon and an army commanded by Kindle and Koal. To destroy it, the Allied Nations have to use some specially adapted anti-sattelite missile silos to destroy the Onyx in under fifty minutes, then attack the Obelisk.
- "Aha ha ha! Not even your delicate little commander knew of its existence! Black Onyx is the black obelisk's guardian angel. In a mere...fifty minutes from now, its barrier field will be operational. Once it's in place, the black obelisk will be safe for all eternity!" —Kindle (Advance Wars: Dual Strike)
- "Black Onyx is equipped with a state-of-the-art particle defence system. The barrier field it projects shields the black obelisk from fire. Our first order of business is to take out the Onyx and drop that shield. [...] Let's get our infantry and mech units out there and capture all the silos. There are...nine silos in all. If we can hit Black Onyx with all nine in under fifty minutes, we can destroy it. We absolutely can't let those missile silos fall into enemy hands! " —Rachel (Advance Wars: Dual Strike)