The school of the multiclass mage gives up the extra powers of other schools instead focusing on ensuring your wizard skills are maximised while focusing on other classes.

Smart enough to manage

Upon 2nd level the multiclass mage has learned to use their intelligence in place of the normal multiclass requirements. They may ignore the multiclass requirements of any other class, but every class they do not meet the requirements for increases the wizard intelligence requirement by 2.

Full spell knowledge

Upon 2nd level the multiclass mage has learned to make up for any lost study time. When learning new spells, the multiclass mage uses either their full character level or twice their wizard level, whichever is lower, to determine what spells they can learn.

Extra knowledge

Upon 6th level the multiclass mage chooses between 3 focus options based on what other classes they have multiclassed into.

If the multiclass mage has multiclassed into a class that gives the extra attack feature at some point, then they may choose the martial focus and gain this other classes extra attack feature.

If the multiclass mage has multiclassed into a class that gives spell slots, then they may choose arcane focus using their full character level to determine the strength of their arcane recovery.

The multiclass mage may instead choose the skill focus, gaining expertise in 2 skills they are proficient in, or proficiency in 2 new skills and expertise in 1 skill.

Arcane focus

If the multiclass mage has multiclassed into a class that gives spell slots, then they may choose arcane focus using their full character level to determine the strength of their arcane recovery.

Martial focus

If the multiclass mage has multiclassed into a class that gives the extra attack feature at some point, then they may choose the martial focus and gain this other classes extra attack feature.

Skill focus

The multiclass mage may instead choose the skill focus, gaining expertise in 2 skills they are proficient in, or proficiency in 2 new skills and expertise in 1 skill.

Full knowledge

Upon 10th level the multiclass mage may choose between an ability score improvement/feat or bringing their magic power to full strength.

If the multiclass mage has multiclassed into a class that does not give spell slots every level, then they may choose to become a full mage and use their full character level to determine their spell slots.

Otherwise the multiclass mage may choose between a feat and an ability score improvment, increasing one score by 2 or two scores by 1, up to a maximum of 20.

Ability improvement

Instead of increasing their magic, the multiclass mage may choose between a feat and an ability score improvment, increasing one score by 2 or two scores by 1, up to a maximum of 20.

Full mage

If the multiclass mage has multiclassed into a class that does not give spell slots every level, then they may choose to become a full mage and use their full character level to determine their spell slots.

Full wizard

Upon 14th level the multiclass mage has learned to make up for any lost wizard studies. They may now use their full character level as their wizard level for determining all features except for arcane recovery and spell slots.