It has 24 Fire and Thunder resistance thanks to the Shadow Shades.

Guard Up is a necessity to block his elemental attacks (namely the eruption and lightning). Shield Jewel might be pretty rare though - if you don't have it, just put in another Critical Boost.

You can also switch out all five of the Lvl1 jewels to get Guard 5, if that is your preference. This would let you enjoy minimum recoil when blocking Behemoth's roars and paw swipes - though the blocking recoil on his elemental attacks seems to be un-reducible. Personally I find that the Shield mod + Guard Up alone is enough for me to tank Behemoth if there isn't a Lancer/Gunlancer around (shoot the paws if you don't want to draw aggro).

The Attack Charm is also not particularly essential ...so between that and the five Lvl1 slots, you have a lot of room for personalization. If you remove the Attack Charm, consider switching one of the Close Range Up mods to a Recoil Suppressor mod - the second Close Range Up mod isn't as valuable without Attack Boost to help it access the next integer in damage-per-pellet.

The non-Layered Shadow Shades's frame is black instead of orange, which could be a big deal for some fashion hunters.