Shadow Giratina (Altered Forme)

In its Shadow forme, Giratina's Altered forme is actually a bit interesting. This is because of the fact that its performance is actually pretty close to Giratina (Origin Forme). This makes sense, as the entire change between Altered and Origin forme is trading a bit of Defense for a bit of Attack, and the changes made by the Shadow boost is extremely close to said difference. For this reason, it's definitely got its utility in PvE as a tanky Ghost Type attacker with decent DPS.

Best PvE Offensive Moveset

• Shadow Claw and Phantom Force* is the way to go with Shadow Giratina - Altered Forme, as it's far-and-away the best moveset that it can pack.
• Dragon Breath and Dragon Claw is the way to go if you want Dragon damage out of Shadow Giratina, but it's VERY mediocre in this role.
• Ancient Power and Shadow Sneak both fall behind by quite a bit.

Shadow Claw and Dragon Breath both have great energy gains and decent damage output. Dragon Breath is generally preferable due to its 1-turn duration, granting Giratina extra flexibility.

Dragon Claw is Giratina's main attack, having decent DPE and benefiting from STAB. Shadow Sneak and Ancient Power are both slightly cheaper, but aren't particularly great moves. Shadow Force is a pitiful move that can sometimes be used for surprise bursts of damage, but isn't great for consistency.