Witch

Witches (or warlocks, who are the male counterparts) are the life state added in Apartment Life. As seen here, they are one of the biggest and most complicated life states in Sims 2.

To become a witch, a Sim must find one, and befriend it. Once done so, a new interaction appears: "Teach Me the Ways of the Light" (if the befriended witch is good) or "Teach Me the Path of Darkness" (if the befriended witch is bad). Once done, the Sim will become either a good or bad witch, depending on which type of witch they befriended, and will have an extended name which includes their alignment, for example, "Bella Goth the Evil witch". They will also receive a a robe, hat, cauldron and spell book. Their colors will be determined by the witch they were received from. The new witch may then purchase goods from other witches, including reagents (see below), as well as a new cauldron or spell book.

Abilities
Witches have many new abilities, including casting spells, crafting exclusive items, creating reagents and potions, being able to travel to other lots via broomstick, teleport around lots and own "feline familiars" (i.e, ghost cats from another dimension).

To cast spells or create potions and items (specifically, thrones, floor lamps, wall lamps and hanging lamps), reagents are required. As said above, these can be obtained by purchasing them from NPC witches, or crafted in a cauldron. Unlike in Makin' Magic, Sims aren't required to pre-prepare spells before casting, but just need the right combination of reagents on the spot. Witches with higher magic skill have a higher success rate when casting spells and have access to the more powerful spells.

Spells
See main article: Spells.

Spells are organized into three categories: "Good", "Neutral" and "Evil". You can study evil, neutral, or good magic in your spell book. This increases your magic skill points, and changes your alignment towards the direction you are studying. It seems that you need to have a perfect alignment in one of the three magics to cast the strongest spells of that alignment. For example a perfectly "good" witch can craft a "throne of light" which is the ultimate chair that charges all motives simultaneously.

Reagents
Magic items/reagents can all be crafted in the cauldron, but some reagents can be bought at the secret magic lot of your alignment.

Alignments
Casting more "Good" spells will result in a witch becoming "Good", and casting even more will make the witch "Infallibly Good". Both alignments wear white robes and hats, craft items which suit the "Good" witch stereotype, and have cauldrons which emit blue smoke. "Infallibly Good" witches also have a blue aura and gold sparkles on their skin. Good spells are intended to improve other Sim's lives, or their environment.

"Neutral" spells have no effect on alignment, but if a witch who is good casts enough evil spells, or vice versa, they can become "Neutral". "Neutral" witches just wear brown robes, and have "normal" looking items, such as a wooden brown spellbook stand. There's no exclusive craftable items for "Neutral" witches.

Once enough "Evil" spells are cast, a witch will become "Evil" or "Atrociously Evil". They will wear black robes, craft gothic-like items, and have a cauldron which emits red smoke. "Atrociously Evil" witches have green skin and a sickly green aura.

Other
It has been rumored that the High Witch is Bella Goth. The Sims 2 Chat confirms that Bella Goth is NOT a High Witch. Wikipedia claims that Merlin (of King Arthur) will be the high "witch". There are two High Witches, one of light and and one of dark. Who they are depends on your neighborhood.

Witches can be combined with other Life states.

Teens through elders can be witches.

Good witches and Evil witches do have a rivalry. Evil witches like to summon Spectral Assistants to do their dirty work.

Witches can visit any secret lot independent of their alignment.

Feline Familiars
If Pets is installed, Witches may discover their feline familiar. Spectral cats can be summoned from "The Void" at any time, and resemble its owner's alignment, and may return to "The Void" when it's too uncomfortable, or when its owner leaves the lot. Feline familiars are like cats, except in appearance, and the lack of the need of a litter box and ability to breed. If treated well, the feline familiar is more likely to stay.