Soldier of the Pantheon

• WOTC Official Reminder Textofficial rules
  Protection — This permanent can't be damaged, enchanted, equipped, blocked, or targeted by [quality].

• WWizards of the Coast2013-09-15
  Official Ruling
  Most hybrid spells and permanents, including the ones in the Return to Ravnica block, are multicolored, even if you cast them with one color of mana.
• WWizards of the Coast2013-09-15
  Official Ruling
  Soldier of the Pantheon can't be enchanted or equipped by multicolored Auras and Equipment, it can't be blocked by multicolored creatures, it can't be targeted by multicolored spells or abilities from multicolored sources, and all damage dealt to it by multicolored sources is prevented.

Rulings via Scryfall