Learn Croatian: Vratio se doma kasno. - He returned home late.

In the Croatian past tense, you usually need the helping verb je for "he", "she", or "it". However, when you use a reflexive verb (a verb that has se), that je is dropped. Saying Vratio se je is incorrect in standard Croatian, so it simply becomes Vratio se.

How do we know it means "he" returned, and not "I" or "you"?

Two things tell us this is "he". First, the verb ends in -o (vratio), which is the masculine singular form. Second, there is no helping verb like sam (for "I") or si (for "you"). Because the helping verb is missing entirely, we know it is the third-person singular ("he"), which drops its helping verb je next to se.

I learned that doma means "at home" (location). Can it also mean "to home" (direction) like in this sentence?

Yes! In strict standard Croatian, you might see kući used for direction (going home) and doma or kod kuće for location (being at home). But in everyday spoken Croatian, people use doma for both direction and location all the time.

Why is se placed right after Vratio?