Built almost as a counterpoint to the Baldur, the Paladin is the Federated Sun's own effort to symbolize its own resurgence as a state after the ruinous civil war.
Produced on New Avalon by Achernar BattleMechs from the repaired factories, the Paladin stands proudly as an all purpose battlemech.

Outfitted with many pieces of advanced technology, one piece of equipment stands out, the class 5 Mydron autocannon. Considered to be outclassed by the modern ultra and LBX class variants, it was interesting why the Paladin employed this obsolete weapon.
It turns out that units in the Federated Suns were having difficulty using the new speciality ammuntion types. The rapid modernization of the AFFS in recent years has proved a double edged sword, with many elite units using more advanced autocannons and unable to use the various autocannon munitions. The Paladin was conceived as a way to introduce the enemies of the Federated Suns to their new ammunition technology, and so mounted the Mydron, along with two tons of ammunition.
McCloud Specials jump jets offer the Paladin excellent mobility for an assault mech, while the heavy armor allows it to withstand great amounts of enemy firepower.

One version that has appeared with the Comguards is the 4C, which   swaps out one of the medium lasers and a bit more armor for a C3i unit.

Arthur Fiat
A well known mercenary in the Inner Sphere, Arthur is infamous for never losing a fight.
EVER.
His first action came in the 4th Succession War, where he fought alongside many Davion forces as a freelance mercenary. Many times, opposing Liao forces, even entire lances, fell before his lone mech. Arthur was awarded numerous medals for his contributions.
Strangely enough, he signed on with the Capellans next, and helped them to beat off the Anduriens and Canopans.
The next few decades saw Arthur fighting for nearly every house in the Inner Sphere, and even one clan, the Jade Falcons, when a merchant escort contract got him into Jade Falcon territory during the Hegira War. The Steel Vipers attacked him, and a pissed off Arthur ended up helping the Falcons thrash the Vipers silly.
A quick review of his contracts revealed that the side he fought for always won, leading people to conclude that either he was an excellent picker of winning sides, or just dumb lucky.
Arthur sat out the FC Civil War, claiming it was too dirty, and is currently pondering signing on with the Star League Defense Force, after helping the Wolf Dragoons kick Wobblie butt all the way back to Terra.
Somehow, Arthur was able to claim a new Paladin from the fighting during the jihad, and the "Implausibility", as he has named his mech, has been known to take down entire companies by itself, via shots using armor piercing ammunition from the autocannon and headchopping from the gauss rifle.

Paladins have appeared in almost all AFFS regular units, as well as some Com Guard divisions, particularly those supporting Victor Davion as Precentor Martial.