Ulquiorra Schiffer is Espada # 4
if your talking about the impure world resurrection, the episode hasn't been made yet, its only happened in the manga
~Spoiler!~ Ichigo.
When Yammy isn't in his released form, Ulquiorra is stronger because he is the Cuarta Espada (the 4th Espada) and Yammy is the Decima Espada (the 10th Espada). But when Yammy is in his released form, he becomes the Ciero Espada (the Zero Espada) and that makes him stronger than Ulquiorra. - Sukineko
Season 8 | Episode 13: "Go Stewie Go"
Ulquiorra fades away in Episode '272. Ichigo vs. Ulquiorra, Conclusion!'
Episode 267
Episode 139
Episode 139
I'm not sure but i think it is in the 260 or something like that. you can try some epsode around 260. When Ulquiorra is fighting Ichigo, he releases in episode 271. Then he releases for a second time in episode 271. Ulquiorra is the only arrancar that has achieved a second release.
when he fights against Ulquiorra, the 4th espada
In episode 267,268,269,270,271. btw its ulquiorra
Episode 140: Ulquiorra's Scheme, the Moment when the Sun Sets!
Actually he didn't save her.After fighting Ulquiorra,Grimmjow took him to Inoue in episode 165.
269 ichigo and ulquiorra release there swords
The episode is not out yet in japan and its over ep 257. Its during his 3rd or 2nd fight with ulquiorra
The episode is called "Resurrection"