Need advice on Karl (Updated, Global)...

I really want to get Karl as a unit...but my team is far too squishy. I'm planning to use my main squad (albeit modified), a mono-thunder squad, and another fodder squad. But, since I have a CRAPTON of units, I don't know who to focus my time on.

Let's get over to the gist of my main squad, shall we?

- Cyborg Lilith II (G), lvl MAX (Leader)
- Magistra Lira (L), lvl MAX
- Drake Angel Aisha (L), lvl 69
- Gun Goddess Serin (B), lvl 71
- Holy Earth Lance (A), lvl 91 (w/ SBB lvl 7)

(Wow...Lance is the only guy in a team full of girls...)

My planned teams (and their current levels):

Modified main squad:

- Cyborg Lilith II (G), lvl MAX
- Princess Emilia (O), lvl 59
- Battle Girl Ophelia (L), lvl 49
- Snow Cub Signas (B), lvl MAX
- Drake Angel Aisha (L), lvl 69

Other squad

- Drake God Lodin (O), lvl 66 (Leader)
- Gun Goddess Serin (B), lvl 71
- God Tree Eltri (O), lvl 66
- Xenon & Estia (G), lvl 48
- Magistra Lira (L), lvl MAX

Mono Thunder

- Holy Thunder Eze (L), lvl 69 (w/SBB lvl 1, leader)
- Raid Bomb Fennia (O), lvl 21
- Gold Warrior Rina (L), lvl 46
- Bolt Goddess Amy (B), lvl 47
- Will get a Royal Dancer May (G) later on

Other noteworthy units:

Fire

- Holy Flame Vargas (L)
- Blade God Seria (L)
- Head Chef Lancia (G)
- Freya (A)
- Hot Rocket Cayena (G)
- God Arm Galant (G)
- Blacksmith Galant (A)
- Fire God Lava (G)
- Lava (L)
- Fire Beast Zegar (L)
- Fire Knight Agni (B)

Water

- Ice Goddess Selena (A)
- Ice Selena (G)
- Dragon Hero Zephu (O)
- Knight Zephu (G)
- Malnaplis (G)
- Leviathan (G)
- Sea King Mega (A)
- War Captain Mega (A)
- Ice Mage Dean (A)
- Frost Queen Stya (L)
- Stya (A)

Earth

- Bow God Lario (L)
- Archer Lario (G)
- Wild Slash Bayley (O)
- Empress Lidith (L)
- Gaia Fist Nemia (L)
- Brawler Nemia (G)
- Earth Knight Edea (L)

Thunder

- Commander Weiss (B)
- Strategist Weiss (A)
- Zele (B)
- Thunder Kick Zeln (L)
- Zeln (G)
- King Behemoth (L)

Light

- Holy Light Atro (B, w/ SBB lvl 1)
- Knight Atro (A)
- Holy Queen Luna (A)
- Maiden Vanila (A)
- Cyborg Lilith (G)
- Legionary Melchio (O)
- Hero Alma (O)
- Sola (B)
- Knight Aem (L, O)
- Estia (B)

Dark

- Unholy Magress (B)
- Heavy Magress (G)
- Hell King Hades (A)
- Madia (G)
- Shadow Oboro (G)
- Lich (A)
- Xenon (B, G)
- God Blade Mifune (B)
- Mifune (G)

I will try to max everyone up...but any help on my squads is appreciated. Thank you in advance!