Lich's Shrine

[Saramoth]

Ok so my party is lvl 21 and they are going against a demilich. So i need some ideas for his shrine, i have a couple of ideas but i need to make it challenging :)

traps, wards, guardians and so forth ^^

[Ignominia]

Golems have always been a go-to guardian for casters.
Couple of Iron Golems could go a long way...

EDIT:Also, if you feel like being especially nasty... look to the Tomb of Horrors adventure for trap ideas. To me, nothing screams Evil Demi-Lich like inescapable death traps.

[Malvanis]

You could install some mithril golems from the epic level handbook. I think they are CR 31. They could serve as tougher gaurdians than the standard iron golem.

[Bromidrosis]

You could install some mithril golems from the epic level handbook. I think they are CR 31.

Pair those with some Shadesteel Golems (MM3) and some greater undead that would benefit from their negative pulse wave ability and the aforementioned death traps. The theme of negative energy/mindless servants would fit a demilich well, and likely be pretty challenging even for an epic level party.

[unseenmage]

The Living Vault from the ELH epic spells section is pretty brutal too if used creatively.