Definitions

[Nystul]

Strange, then, how do they define Ultra-pure?

Pushing a lot further into the category of self-restricting playing styles. It's a specific rule set made by Claudio, as quoted below:

Ultra-Pure means:
Legit
Pure
And:
The Ultra-Pure character can only buy blue/red/yellow potions, townportal scrolls and scrolls of resurrect for multiplayer games. All other items (books, elixirs, weapons and armors) must be found in the dungeon. Besides this restriction, the Ultra-Pure character has full access to the town: identify items, sell items, repair items, recharge staffs and healing chez Pepin. No storage characters are allowed, just your 40 inventory slots. An Ultra-Pure character shouldn�t enter, with the help of high level characters, areas that are to dangerous for her/him. An Ultra-Pure character should make a 3@30 run (optional). An Ultra-Pure character shouldn't play with known cheaters or with characters of much higher clevel (unimportant after 3@30 is done).

Some Rule-clarifications:
The Ultra-Pure character can buy any kind of weapons and armors and pass it over to other legit characters or friends, but must not use it. The Ultra-Pure character can buy a non-magical or magical item, if she/he finds a hidden shrine and want to replace an indestructable item to use the shrine. After using the shrine this item must be replaced/dropped.

http://web.archive.org/web/19991004151003/.../www.catbwo.de/

Wonder what Claudio is up to these days?