This deck is part of a fellowship designed to use all the cards from the Black Serpent. As a result it's a bit bloated and inefficient.
Since Southron Refugee is one of the cards, that meant this needed to feature Kahliel, so he's in here along with 2 copies of his big allies, three copies of Kahliel’s Tribesman, 2 copies of Kahliel's Headdress and even a lone Haradrim Spear.
The desire to support Scouting Party led to two scouts, Hirgon and Elfhelm to be the other two heroes. Conveniently, they're Gondor or Rohan to enable use of Oath of Eorl and scout/warrior for Hunting Party. Hirgon's ability makes Defender of Cair Andros cheaper, and if he uses his threat raise it will make their defense better permanently.
Burst into Song and Song of Hope work together, though there's a ton of songs in the other deck as well.
Hirgon's ability makes him a natural target for The Red Arrow, but he can also put out Honour Guard cheaply to support Fastred in the other deck. Fastred also has some other support with Golden Shield, Captain of Gondor, Dúnedain Warning and Armored Destrier. Dúnhere is supported with Dúnedain Mark, Spear of the Mark, Firefoot and Rohan Warhorse, though the last two can go on heroes on this deck (in Kahliel's case, after he's given Steward of Gondor. Arod can go on any hero and isn't restricted, so while it'd be best on Dunhere it can go on anyone in a pinch. Raiment of War can go on Fastred at the expense of using both restricted slots, but would also work exceptionally well on Jubayr. Rosie Cotton is the lone suport card in this deck for Pippin.