This morning Cassandra Clare answered a question about Church on her Tumblr (cassandraclare.tumblr.com)
Question: “Is Church the cat in TMI the same cat as in ID?”
Cassandra Clare: I guess it’s time to come clean. Church the cat in The Mortal Instruments is actually Tessa.
I can’t speak about the tragic events at the end of Clockwork Princess, but let’s just say that Tessa is left alone to fend for herself. She’s learned to transform into animals as well as people so she transforms into Church and hitches a ride with Magnus when he emigrates to New York. Disguised as a cat, she is safe from Mortmain and his evil minions, so she stays that way and moves into the Institute when she hears the Lightwoods are taking over since she remembers Gideon fondly, despite the incident with the hurdy-gurdy that made Sophie realize she could never love him.
When the Mortal War breaks out and the Lightwoods all leave Church behind Tessa realizes she still owes the Shadowhunters loyalty and follows Magnus to Idris to take part in the battle. That’s why she has her human form in the scene where Clary glimpses her at the end of Glass. The reason she looks familiar to Clary is that she has not completely transformed back and still has cat ears.
Also, many have asked what she and Magnus are discussing. Tessa knows Magnus owns a cat and is hoping he can convince the Lightwoods to change their brand of dry cat food.
Also, you should definitely read the tags on this one.
(the tags read: ‘April Fool’s’ ‘I had to do something’ ‘not as bad as last years’)
Who loves Cassie? 🙂
Happy April Fool’s Day! And also, happy birthday to the Weasley twins! )’: