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 has good damage with great energy gain. Dragon Breath can also be viable for its superior damage output, but results in less usage of Giratina's charge moves. Generally speaking, Shadow Claw is preferred in the Master League, but both Fast Attacks are viable in the Ultra League.

Dragon Claw costs the least amount of energy, gets STAB, and can be used very frequently. Shadow Sneak is pitiful, but offers consistent Ghost coverage to pressure most Dragon resists. Ancient Power can offer coverage against some Ice-type Pokemon and certain other threats such as Mandibuzz and Lapras. Shadow Force, Giratina's signature move, is intentionally given horrendous PvP parameters for balance reasons, but is a viable alternative as a closing nuke and is more effective than Shadow Sneak at beating tanky Pokemon.