There are ten weapons that cannot be easily implemented in game since they are so obviously tied up eslewhere:
- Rydill
- Masamune
- Durandal
- Aegis
- Gungnir
- Sargatanas
- Balmung
- Hyperion
- Excalibur
- Ragnarok

Gilgamesh has this habit of breaking the fourth wall. All the more reason to let him wield them.