My raiding monoblue is composed of Athena, Frida, Sapphire, Lepus and Ariel (all can fire in 9 tiles or lower, except Ariel). Against red titans, I use Miki, Athena, Frida, Lepus and Ariel or Jott (the latter if I want to score over 200k in a single hit). My strategy is to debuff regular defense (Athena or Isarnia or costumed Magni or Frank or Grimm), debuff ice elemental defense (Frida or King Arthur or Nordri). This is followed up by Lepus to kill 2 or 3 heroes targeted by the previous 2 heroes. Sapphire+20 replaced by stripped and unemblemed Vela. Ariel for heal and mana regen bonus. Jott for enhanced tile damage. Miki as attack booster.
The best regular defense debuffer for ice hero is Athena. This is followed by Isarnia at - 44%. Same with Frank and costumed Gunnar though 4* and 3* heroes, respectively. The rest of the ice regular defense debuffer only can reduce defense at -34%, IIRC.
For elemental defense debuffer: choices are Frida and King Arthur. Nordri is just a 3* version and easily gets killed.
My suggestion: Glenda should be flanked by Magni and Lepus. Glenda will greatly enhanced the special damage caused by her flanks. You just need to be able to fire her in 9 tiles so the synergy would be great with Magni and Lepus. Costumed Kiril (who can fire in 9 tiles just by supporting him with a level 5 mana troop due to the costume bonus) will serve as your healer and regular defense debuffer. Sapphire will benefit much to the defense down caused by cKiril.
Against red titans, (an attack booster, preferably Miki, or Tarlak, Gazelle, Ranbir or Wu Kong will do), cKiril, (elemental defense debuffer, if any), Magni, and an ice hero with high attack stat or perhaps a 2nd Kiril with maxed costume bonus to buff attack and defense to allies.
Just my 2 cents.