Ma Lin gives you his Moon and Sun dual blades if you survive the fight without going below 50 hp
One of the Liang shan lords gives you his unique Podao (Glaive?) weapon which is also pretty sweet, though im more of a onehanded warrior guy

I turn the difficulty way down on these battles. Some of the playable lords are just too pathetic and the arenas are too limited. I remember one of the guys had a crappy hammer. No wonder he lost this fight originally.

It's more manageable at 1/4'th damage. The high speed of being on a horse + an attack on a lord that's charging you means you can 1 shot them often. With practice you can score multiple 1 shots. There's a title that gets you two uses of the life saving pills, which I then use to great effect on the final enemy.

I fell you bro - the difficulty and the set up you get (unmounted vs several mounted enemies; enemies having viriety of weapons) is ridiculus

Best tip for the bad lords is to ditch your weapon and grab theirs.
"The something road" fight gives you a flag to fight with XD
You need to quickly kill the guy on the horse in the opening charge and take his Han Spear(one of the best in the game)
The hammer guy is freaking terrible, you can't hit anything with it, but the one unarmored enemy has a silver long saber that makes the fight 1000% easier.
Turn on automatic blocking and slow down the fights; they are a good challenge but doable.

Cheese the fights by exploiting the AI. Units are horseback you should never dismount. Simply get them stuck against a wall, dismount yourself, and stab them in the back.

In those "1 vs 8" fights, if you are on a horse, take out any range units first with a charge/lance attack, then circle the enemy constantly and attack only sparingly. The only lord I'm struggling with is Bao Xu, because two of the enemies are spear throwers with shields.