Update: Breaking solo adventure with Sn1p-Sn4p. Finally got my Arthas, Paladin alternate hero after beating The Lich King (with the help of the Sn1p-Sn4p combo). Deck lists in the comments section. :
The Lich King Boss Adventure - Aggro Murloc Rogue Deck List Guide - Hearthstone Top Decks
Hearthstone: How to defeat The Lich King with all 9 classes
Guide to beating Hearthstone's Lich King with every class | PC Gamer
Maybe a good way to beat Lich King with rogue? Play mastaera become. He gets armor . Break it and kill him with Dmg spells? : r/hearthstone
A list for those whole haven't beaten Lich King : r/hearthstone
Hearthstone: How to defeat The Lich King with all 9 classes
The Lich King Boss Guide - The Frozen Throne - Frozen Throne Adventure - Guides - HearthPwn