Expanding the Schools of Magic (DMG)

Currently, the different schools of wizard magic are merely sketched out and very lightly defined. The different schools can be used as described, but they lack detail and, in a few cases, a full range of spells. There are, for example, very few necromantic spells, thus discouraging player characters from being necromancer specialists. There is nothing wrong in this—nothing requires schools of magic to be equal. However, you might want to customize and expand the schools of magic to suit your campaign.
==Adding New Spells==
A school can be expanded simply by adding new spells. The necromantic specialization could be made more appealing if a complete spell list were created. Be careful that the new spells don't make the school too powerful. In the case of the necromantic school, the first reaction is to add some of the priest healing spells. However, this takes from the role of the cleric and makes the necromantic specialist too powerful. In the long run, it's probably better to create new necromantic spells, spells that do not involve healing or do so only in a minor way. Careful judgment must be applied when adding new spells.
==Expansion Through Campaign Detail==
Although the term "school " is used throughout the Player's Handbook and this book there are no rules to explain any formal structures or institutions. There is no hard and fast definition of a necromantic school. There may or may not be such a school in the campaign. This choice is left to individual DMs.
One possibility is that wizards learn their specialties without formal training. Materros the Necromancer has a natural curiosity about necromantic spells, so he specializes in them.
Another possibility is that there are formal colleges or academies where spells are taught. These institutions would have their own hierarchies, traditions, regulations, and procedures.
:For example, Materros the Necromancer could be a brother of the Cabal of Thar-Zad, a necromantic society. As a sign of his standing high within its hierarchy, he is allowed to wear the red and green robes of a master. Of course, when he wears these, his occupation is easily identified by those who know something of the Cabal. This is not all bad, since the Cabal of Thar-Zad has a reputation as a dangerous and mean bunch. By adding such details, the DM brings his campaign to life. He can make a seemingly limited magical school more appealing to players.