In Monster Hunter World, the Lance received a new defensive stance, the power guard, which lets it block even the most powerful attacks without flinching, but at the cost of a steady stamina drain.
Given the increased guarding capabilities of this move, I'm wondering whether it can also block attacks that normally require the Guard Up armor skill to block: attacks like Pukei-Pukei's poison cloud, Uragaan's sleep and fire clouds, and laser attacks from various monsters.
Iceborne added the ability to empower Power Guard, in which you maintain Power Guard for one second to actually block normally unblockable (as per the Guard Up text) attacks. Your body will flash once more so you will know when it happens.
This means that telegraphed unblockables such as Teostra's Supernova and Vaal Hazak's effluvial beams can now be blocked without Guard Up if you time your guard. However, fast unblockables such as Behemoth's shockwaves and Lunastra's ground explosion don't give you that much time, so you still have to rely on Guard Up for such unblockable speedsters.
In base World, no, the power guard is not a substitute for Guard Up. Trying to power guard an unblockable attack without Guard Up will result in getting hit as normal.
