Arc 6Hueco Mundo and the Stolen Pass
Duan Mu entered Hueco Mundo to rescue the Fujiwara siblings, fought powerful Arrancar, and survived with Tier Harribel’s help before returning to Soul Society. Back in Seireitei, he pursued new work and uncovered Iwao’s impulsive attempt to reach Hueco Mundo with his stolen pass.
- Duan Mu accepted a commission to rescue Fujiwara Hisashi and Fujiwara Rei in Hueco Mundo, where he encountered Shiba Kaien and then fought Aaroniero and Nnoitra.
- After Nnoitra wounded him, Duan Mu hid beneath a Gillian, and Tier Harribel found him and helped him recover while he studied her Hollow powers.
- Duan Mu developed an advanced Hollow Crest for Tier, then escaped Hueco Mundo and reported the Arrancar threat to Yamamoto and the captains.
- Duan Mu returned to his duties, trained his reiatsu, and later killed Grand Fisher after it attacked Kurosaki Masaki and young Ichigo.
- Duan Mu met Ukitake Jushiro through Omaeda and learned that Amanen Nayula had observed him on her own initiative.
- Urahara Kisuke gave Duan Mu a token to the Shiba Clan’s secret archive, and Duan Mu later discovered that his Pass Token had been stolen.
- Duan Mu learned that Iwao had taken the token to reach Hueco Mundo and confront the Hollow impersonating Kaien, then beat Iwao after rebuking him.