Once the spellcasting considerations are satisfied, the wizard proceeds to the next, equally important step: the making of a phylactery, a vessel to house his spirit. The phylactery usually is a small boxlike amulet made of common materials, highly crafted. Lead or another black or dark gray material is frequently used.
Inspection of an amulet may reveal various arcane symbols carved into the interior walls of the box, and those grooves are filled with silver as pure as the mage can find. These amulets are never made of wood, and rarely of steel. Brightly colored metals, such as gold, are infrequently used. (Mirinalithiar's account is extremely unclear, but it may not be the color that is the problem. The relative softness of the material and its subsequent likelihood of being injured may create this restriction.)
The mage understandably has no desire for anyone to learn what ritual is being undertaken, or the appearance of the arcane symbols and etchings he must use. Thus, the mage alone will melt and forge those precious metals, as well as learn whatever other crafting skills are necessary to design and construct the phylactery.
~ Van Richten's Guide to Liches
So you're inside a phylactery. Well done.
Some environmental conditions to consider:
- Shoddy Workmanship: Everything -- the furniture, the food, the very stones that make up the lich's keep will dissolve into colorless marshmallow goop if the object takes at least six points of magical damage. Some liches may augment that durability to suit specific purposes or areas. For instance, the walls of a cell inside a dungeon would naturally be of higher concentration. At a glance this may suggest that tunneling through the sub-world would be no real challenge. Actually that would be highly problematic -- without taking time-consuming precautions, you and your party would quickly find yourselves drowning in the thick goop this sort of activity would generate.
- Ambient Moral Ambiguity: Alignment doesn't "work" here. Any ability or item that requires a specific alignment will work for any of the above. Or none. It just won't care anymore, ok?
- Psionic Weather Patterns: Mental leakage from the minds of its occupants pools inside the boundaries of the sub-world and congeals into a stewing vapor. Weeks of accumulation will result in the formation of sickly, gloaming thunderheads that squeal and rant unintelligibly above. Any who dream during these periods risks mental dislocation and may awake to find that they occupy another party member's body or no body at all. Such a situation could cause a chain reaction of body-swapping and body-ejection of which no good can come.
- Spell Materialization: Any spells you're carrying in your head are visible inside a phylactery. They take semi-translucent forms that vaguely resemble balloon animals and obscure types of ocean life in a myriad of colors and gloamings. They do not speak or produce audible chatter of any sort until the very moment they are cast, screaming in ecstasy as they transmute into their incantated effects. While they are in their uncast, inert state spells will cling to their magic-user like infantile creatures hanging on their mother, licking his skin with their squeaky balloon-tongues and twisting playful knots into his beard. Any wizard who sees a manifested spell-creature will immediately know its identity if that spell is part of his own repertoire.