Lulli

Lulli is a robot girl who appears in "A Beautiful Girl that Nobita Loved".
She shares a similar personality to Roboko. However, she hates being abandoned, especially by the one boy she cares about the most, Nobita. Also, she views anyone who mercilessly bullies Nobita, including Gian and Suneo, as evil and beat them up in order to protect him.
Her serial number is B-0625.

(Source: Doraemon Wiki)