You can Special Summon this card (from your hand) by sending 3 face-up "Fire Formation" Spell/Trap Cards you control to the Graveyard. When this card is Normal or Special Summoned: You can Set 1 "Fire Formation" Trap Card directly from your Deck. You can only use this effect of "Brotherhood of the Fire Fist - Swallow" once per turn. Face-up Beast-Warrior-Type monsters you control cannot be targeted by your opponent's card effects.
Fire Formation - Tensu allows you to Normal summon another Beast-Warrior type monster, in addition to your Normal summon/Set. It also grants 100 ATK to all your Beast-Warrior type monsters. Fire Formation - Tenken is equipped to 1 of your Beast-Warrior type monster, and negates its effect, while making it unaffected by any card effects except this card (This applies even after Fire Formation - Tenken leaves the field). In addition to that, it also grants 300 ATK to all your Beast-Warrior Type monsters.
Make sure you're not assuming that it grants Beast-Warriors card effect immunity. It just prevents them from being targeted. Still able to be affected by cards like Super Rush Headlong, Mirror Wall and Wall of Destruction.