Just wonder, except wang yuan ji...still got which general can fill triple attack gauge faster ?
Think bao san niang also quite fast...
Depends on whether you mean by weapons or by an ability. For example, Nemea raises it for every 100 kills you get (only needs to be in your party, doesn't need to be doing the killing) and any character will raise it much faster with the Confluence ability on their weapon.
But base, yeah really any character whose weapon racks up the combo gauge fast (hitting multiple enemies with a single attack) will raise it quickly. Also, horseback can help depending on the char.
"A mind needs books like a sword needs a whetstone." -Tyrion Lannister
now i test it with every general...
Zhu Rong is really good for filling up the triple attack guage!
... AAANNNDDDD.... that's about all she's good for.
Zhang He C2 fills it fast, if you do the drill claw (triangle) at the end of it.
"I cannot take pride in such a meager endeavor." -Mitsunari Ishida
after try almost every character i find out that the black hole musou of Guo Jia is the best way to fill the triple gauge, it can fill this gauge from empty to full almost instant
Kanbei's musou fills it up pretty fast as well, especially if you have all four orbs out/or verity(which autotriggers 4 orbs) when you do it.
And Oichi, musou especially.
I've boned a troll and wreaked some wrath, but on the whole I've had no path.
Ina's R1 specail works wonders in a crowd for the Triple Gauge.
~ I am going to purify your soul ~
Susano C4, with confluence