I am currently in town 5 at about 50%, and my team is working fine, but it doesn't work that well in Arena. This is the current setup I use:

Heroic Beasts: Passive: Raise team's MAX HP by 50%. (Celestial Lion / Giant Eagle)
5* T1 Guardian Angel lvl 27 (10159 HP, 2385 ATK, Bless: Recover HP to this card's team)
4* T4 Taal lvl 21 (10822 HP, 3018 ATK, Guardian: Recover HP to this card's team)
3* T2 Celestial Lion lvl 14 (6418 HP, 1681 ATK, Deafening Roar: Lower ATK of enemy team)
3* T1 Giant Eagle lvl 12 (3521 HP, 870 ATK, Dive Attack: Raise ATK of your team with the highest ATK but reduces HP)

Gifted and Talented Passive: increase Skill Proc of team members by 15%. (Bard / Battlemage)
Druid Beats: Chance to revive team with 20% HP upon death. (Elder shaman / Bard / Primal Warrior)
4* T1 Elder Shaman lvl 40 (10035 HP, 3102 ATK, Rally: Raise ATK of your party when this card is at MAX level)
3* T3 Primal Warrior lvl 16 (7243 HP, 2281 ATK, Primal Strength: Raise ATK of your party when this card is at MAX level)
4* T4 Battlemage lvl 15 (12792 HP, 3115 ATK, Fireball: Damage and lower ATK of enemy team with the highest ATK)
3* T1 Bard lvl 10 (3983 HP, 977 ATK, Bard Music: Raise ATK and recover HP to your leader team)

Cultists: Chance to revive team with 50% HP upon death. (Necros the Grim / Father Maleficent)
Twin Clerics: Increase ATK by 30% when HP falls below 70%. (War Cleric / Father Maleficent)
6* T4 Fenric Gore-Claw lvl 32 (19128 HP, 6017 ATK, Rend: Raise ATK and recover HP to this card's team)
5* T4 Necros the Grim lvl 22 (14411 HP, 4538 ATK, Wall of Souls: Create a strong shield on this card's team but reduces ATK)
4* T4 Father Maleficent lvl 12 (9183 HP, 2911 ATK, Shield of Shadows: Create a shield on this card's team)
3* T1 War Cleric lvl 10 (3395 HP, 843 ATK, Cure Wounds: Recover HP to this card's team)
Total HP / ATK / Mana: 111090 / 31738 / 92
These are the cards I have available:
5* T1 Fenric Gore-Claw lvl 1 x7
5* T1 Morbius the Cursed lvl 17 (7796 HP, 2444 ATK, Curse of the Dead: Lower ATK of enemy party) / lvl 1 x2
4* T1 Elder Shaman lvl 36 (Gonna use this to evolve when it hits max lvl)
4* T1 Ysbadden lvl 18 (6381 HP, 1992 ATK, Tremors: raise ATK to this card's team on its first attack)
4* T1 Black Knight lvl 18 (5815 HP, 1841 ATK, Black Magic: Sacrifice HP of this card's team but greatly increase ATK)
4* T1 Guinevere lvl 1 (4680 HP, 1144 ATK, Queens Blessing: Recover HP to your team with the highest HP)
3* T3 Doomweaver lvl 10 (8246 HP, 2558 ATK, Web Blast: Lower ATK of enemy party when this card is at MAX level)
3* T1 Grail Knight lvl 7 (4572 HP, 991 ATK, Hero's Fortune: Recover HP to this card's team)
3* T1 Alpha Stag lvl 1 x2 (2611 HP, 846 ATK, Stampede: Raise ATK of this card's team on their first attack)
3* T1 Armored Warhorse lvl 1 (3320 HP, 808 ATK, Horse Milk: Recover HP to your team with the highest HP)
3* T1 Ice Mage lvl 1 (3766 HP, 910 ATK, Icicle Blast: Damage enemy team with the lowest HP)
Possible Combo's:
Heroic Beasts: Passive - Raise team's MAX HP by 50%. (Celestial Lion / Giant Eagle)
Gifted and Talented: Passive - increase Skill Proc of team members by 15%. (Bard / Battlemage)
Druid Beats: Chance to revive team with 20% HP upon death. (Elder shaman / Bard / Primal Warrior)
Cultists: Chance to revive team with 50% HP upon death. (Necros the Grim / Father Maleficent)
Twin Clerics: Increase ATK by 30% when HP falls below 70%. (War Cleric / Father Maleficent)
Blessed Stag Rider: Passive - Reduce damage taken by 20%. (Primal Warrior / Alpha Stag / Guardian Angel)
Blessed Knight Rider: Passive - Reduce damage taken by 20%. (Grail Knight / Armored Warhorse / Guardian Angel)
Please leave any suggestions below, I can farm cards to enhance so don't mind the lvl's too much.
Thank you - Montgomerie

Heroic Beasts: Passive: Raise team's MAX HP by 50%. (Celestial Lion / Giant Eagle)
5* T1 Guardian Angel lvl 27 (10159 HP, 2385 ATK, Bless: Recover HP to this card's team)
4* T4 Taal lvl 21 (10822 HP, 3018 ATK, Guardian: Recover HP to this card's team)
3* T2 Celestial Lion lvl 14 (6418 HP, 1681 ATK, Deafening Roar: Lower ATK of enemy team)
3* T1 Giant Eagle lvl 12 (3521 HP, 870 ATK, Dive Attack: Raise ATK of your team with the highest ATK but reduces HP)

Gifted and Talented Passive: increase Skill Proc of team members by 15%. (Bard / Battlemage)
Druid Beats: Chance to revive team with 20% HP upon death. (Elder shaman / Bard / Primal Warrior)
4* T1 Elder Shaman lvl 40 (10035 HP, 3102 ATK, Rally: Raise ATK of your party when this card is at MAX level)
3* T3 Primal Warrior lvl 16 (7243 HP, 2281 ATK, Primal Strength: Raise ATK of your party when this card is at MAX level)
4* T4 Battlemage lvl 15 (12792 HP, 3115 ATK, Fireball: Damage and lower ATK of enemy team with the highest ATK)
3* T1 Bard lvl 10 (3983 HP, 977 ATK, Bard Music: Raise ATK and recover HP to your leader team)

Cultists: Chance to revive team with 50% HP upon death. (Necros the Grim / Father Maleficent)
Twin Clerics: Increase ATK by 30% when HP falls below 70%. (War Cleric / Father Maleficent)
6* T4 Fenric Gore-Claw lvl 32 (19128 HP, 6017 ATK, Rend: Raise ATK and recover HP to this card's team)
5* T4 Necros the Grim lvl 22 (14411 HP, 4538 ATK, Wall of Souls: Create a strong shield on this card's team but reduces ATK)
4* T4 Father Maleficent lvl 12 (9183 HP, 2911 ATK, Shield of Shadows: Create a shield on this card's team)
3* T1 War Cleric lvl 10 (3395 HP, 843 ATK, Cure Wounds: Recover HP to this card's team)
Total HP / ATK / Mana: 111090 / 31738 / 92
These are the cards I have available:
5* T1 Fenric Gore-Claw lvl 1 x7
5* T1 Morbius the Cursed lvl 17 (7796 HP, 2444 ATK, Curse of the Dead: Lower ATK of enemy party) / lvl 1 x2
4* T1 Elder Shaman lvl 36 (Gonna use this to evolve when it hits max lvl)
4* T1 Ysbadden lvl 18 (6381 HP, 1992 ATK, Tremors: raise ATK to this card's team on its first attack)
4* T1 Black Knight lvl 18 (5815 HP, 1841 ATK, Black Magic: Sacrifice HP of this card's team but greatly increase ATK)
4* T1 Guinevere lvl 1 (4680 HP, 1144 ATK, Queens Blessing: Recover HP to your team with the highest HP)
3* T3 Doomweaver lvl 10 (8246 HP, 2558 ATK, Web Blast: Lower ATK of enemy party when this card is at MAX level)
3* T1 Grail Knight lvl 7 (4572 HP, 991 ATK, Hero's Fortune: Recover HP to this card's team)
3* T1 Alpha Stag lvl 1 x2 (2611 HP, 846 ATK, Stampede: Raise ATK of this card's team on their first attack)
3* T1 Armored Warhorse lvl 1 (3320 HP, 808 ATK, Horse Milk: Recover HP to your team with the highest HP)
3* T1 Ice Mage lvl 1 (3766 HP, 910 ATK, Icicle Blast: Damage enemy team with the lowest HP)
Possible Combo's:
Heroic Beasts: Passive - Raise team's MAX HP by 50%. (Celestial Lion / Giant Eagle)
Gifted and Talented: Passive - increase Skill Proc of team members by 15%. (Bard / Battlemage)
Druid Beats: Chance to revive team with 20% HP upon death. (Elder shaman / Bard / Primal Warrior)
Cultists: Chance to revive team with 50% HP upon death. (Necros the Grim / Father Maleficent)
Twin Clerics: Increase ATK by 30% when HP falls below 70%. (War Cleric / Father Maleficent)
Blessed Stag Rider: Passive - Reduce damage taken by 20%. (Primal Warrior / Alpha Stag / Guardian Angel)
Blessed Knight Rider: Passive - Reduce damage taken by 20%. (Grail Knight / Armored Warhorse / Guardian Angel)
Please leave any suggestions below, I can farm cards to enhance so don't mind the lvl's too much.
Thank you - Montgomerie