Raid 5

Raid 5 is a very difficult content, you will need good runes too, not just the right mobs.

For a safe (lie, in R5 nothing is safe), but not to slow team you should use:
1) One Damage reduction unit (like Dias, Darion, or Def+ buff)
2) One/Two Cleaner. One if it has the skill every 3 turns (like Kona, or Anavel). If you want to be safer put in a second one (like Lisa or Amarna) even if it has 4-5 turns CD.
3) Attack buff. Use Bastet or Colleen because she puts Atk- and Uncoverable to the Boss. Debuff are very important here!! (remember that if you use Bastet you needs one more healer on the team).
4) Damage Dealers based of Harmful effects are the best here (like Brandia and the Xiao Lin), but Fei, Hwa, Mei Hou Wang are good units too for Raid.

FRONTLINE:
Dias/Darion (at least 1 set on revenge runes, 70% resist HP DEF DEF/HP).
Bastet/Colleen (don’t need violent runes, just very fast and tanky SPD HP DEF/HP).
Xiong Fei/Mei Hou Wang (if you use this front, put the front unit with less Def in Backline)
Cleaners:
If you use Bastet –> Anavel/Amarna (if you have) and Kona 
If you use Colleen –> Kona/Anavel/Amarna (if you have) and Lisa/Dona(light penguin)

BACKLINE:
Hwa, Brandia, Xiao Lin, Fei, Homunculus Wind and/or Cadiz.

In R5 the Leader skill used are: Def, Resist, Rate.
So if you have Dias/Praha, Baster/Xiong Fei/ Mei Hou Wang and Hwa in your team, you will not have problems.

Good luck and have fun.