In Episode 13, Kaos totally curb-stomping Teppei while trying to find out if he is worthy enough to take the Machine Empire.
In the same episode, Teppei actually managing to land a hit on Kaos through an Indy Ploy.
In the manga, Amigo climbing out of Underhell, WHILE carrying Kotaro, with little to no oxygen left in the air.
Mythrim gets a Villainous Valor moment in the anime series, managing to take a second wind against Teppei after his B't was destroyed.
The OVA for going a bit Gainax Ending but providing a much more awesome if tragic Downer Ending than the original manga, to the tune of THIS music. Kotaro and Dr. Lisa Maria Stein figure the molecular structure of the gem inside the capsule has the power to cause the light-generating reaction required to eradicate Raphaello. Then, as Kotaro plunges to give it to Teppei for the last assault, the Four Generals have a Heroic Second Wind and form what Dr. Lisa realizes is the same shape as the crystal in the capsule, amplifying the light. This means they had as big a role to play as Teppei in defeating the monster, even if every main character had to die for it to happen.
Hokuto has what is mostly a duel of wits with a former school comrade, Poe, and wins the day via Awesomeness by Analysis.
. Kotaro and Dr. Lisa Maria Stein figure the molecular structure of the gem inside the capsule has the power to cause the light-generating reaction required to eradicate Raphaello. Then, as Kotaro plunges to give it to Teppei for the last assault, the Four Generals have a Heroic Second Wind and form what Dr. Lisa realizes is the same shape as the crystal in the capsule, amplifying the light. This means they had as big a role to play as Teppei in defeating the monster, even if every main character had to die for it to happen.