Mei attempts to explain something very important to Sagiri's party in the forest. Shion tries to explain how he interacts with the world to Nurugai. A mysterious servant of the Tensen tries to explain why Aza Chobe and Toma shouldn't escape.
Maybe by "tanden," she means what 
the navel is called in martial arts.
.ربّما تقصد بـ"تاندن" ما تدعى السّرّة في فنون القتال
Das Zentrum … So nennt man in
der Kampfkunst doch den Nabel, oder?
"Tanden" en las artes marciales
se refiere al ombligo, ¿no?
Quizá "tanden" se refiera
al ombligo en artes marciales.
« Tanden » ? Elle parle du nombril
dans les arts martiaux ?
Ha detto dantian...
Nelle arti marziali significa ombelico, no?
Acho que "tanden" é o termo usado
para "umbigo" nas artes marciais.
Даньтянь?..