Both Jack and Kazama with their Big Damn Heroes moments in Chapter 26. Jack's involves jumping over the central lane of the Highway to meet up with Crow on the opposite side - with Yusei between them. While Kazama literally appears from the destruction of the roads to save Yusei before it collapses completely.
Despite being quite a delicate character, Ruka stands up to Aki's aggressive mood through the same chapter. Even when she's beaten, she's able to stand and continues to be defiant to Aki's preference of being alone rather than joining the Signers.