Its kinda lame dont you think? feels disorder...
Basically:
- You can warp them to you (if you're not in a non-/memoable map). It's *the* way to get out of unpathable places if you have no FW/BW without having a GM respawn you (you used to warp people out of jail even, but GMs don't jail anymore

).
- You can recover their SP by 10% per cast (good if you're a fast SP recovering class and the other one isn't, or the other way round - if you use a lot of SP and they don't - they can just give you like 20% real quick if you run out).
- You can recover their HP by 10% per cast (this goes through GTB and through the undead status. Especially good if you're not a heal-class and the other one is.)
- If you're a SL, you can give them Ka*-Buffs even if you're not linked.
- If you're a SN, you get a number of other buffs that I don't remember

Of course, you need to know the person you're "marrying" - best if you know them outside-RO, I'd say
