Characters, monsters and items can also be aligned with multiple attributes at once. For example, a staff weapon is generally about 70% strength and 30% intelligence. It differs from a maul (which could be 100% strength) because it is better at scoring critical strikes, but doesn't hit for as much raw physical damage.
There are four playable "hybrid" character classes in Path of Exile: The Duelist, the Templar, the Shadow and the Scion.
Players can use any items or skills, providing they have enough of the relevant attribute requirements. There is the flexibility to dabble in unaligned attributes in order to use off-class skills and items. However, it is generally more efficient for players to invest in the attributes appropriate to their character class.