User blog comment:B214/High School DxD New Episode 3 Discussion/@comment-16075832-20130722160729/@comment-1359322-20130723024917

The anime didn't really showed it but in the light novel, you'll know that Irina bought a fake painting and loss all of their money and then they do the "begging for fund" sort of thing until they saw Issei, Koneko and Saji and looked at them with hungry eyes, then the lunch scene as you seen, then during that Issei asked to form an alliance with the 2, where Issei and the others will assist them in retrieving the Excaliburs while they will hand one of them so that Kiba can destroy it. Xenovia accepted since she felt that this was a suicide mission and also her superior never said that they couldn't receive the help of a "Dragon".