I've read these old stories too lol
As i said large bear is only carnivore i would not consider the underdog, have the tools and size to probably be more or less 50/50
Said that old stories are old stories lol, don't buy bear killing multiple bulls consecutively (and if he did sure af we're not speaking legit roidrage spanish corrida bulls), just like i find exagerate other stories of lion killing multiple tigers, tiger killing multiple lions, fucking rhino killing multiple elephants (all stuff i've actually read), people just loved these stories back then lol
Plus you have to add these shows ever been rigged as fuck since Rome days, lot of shit was done in animal fights (and even gladiators ones) to obtain gambling profits
I've no problem believe large bear killing corrida bull and if he's lucky even not getting heavy injuried in the process... but do it multiple times in a row you're either using shitty cattle or story itself is probably fake
To give an idea using american bison wikipedia page
"
Grizzly bears are known to feed on carcass and may steal wolves' kills. While grizzlies can also pose a threat to calves and sometimes old, injured, or sick adult bison, direct killing of non-calves is rare even when targeting lone and injured young individuals;
[86][87][88] attacking healthy bison is risky for bears, who can be killed instead.
[89][90]"
Now, american bison and spanish corrida bull are different animals, but still offer perspective