Can be a magic tank especially with Rune Blade weapon from raid reward in future, or magic attacker with Crimson Saber weapon from Tower reward.

Just got rain and mediena? which one is better?

I pulled Rain and Mediena, and a i have a 4 stars Ayaka. I can max awaken only 2 of this 3. What do you suggest?

If you need a magic tank, do Rain. Otherwise, go Mediena for dps; she has more AOE skills and DPS. Also, try to max awaken Ayaka as she would probably be most helpful in healing your team for future events etc.

Mediena was great in March. In the modern world, Rain is much better. Mediena is basically useless except for farming.

elsewhere was said rain is only good at killing ice units, where others have more general utility, after lard rain is probably out for pasture
Also at this point medi is for glass cannon lowbies in guild war