Sakugi Mitsuaki is a poor college student who gets hooked on figure modeling. In return for helping his class he receives some special putty -- but the figure he builds with it suddenly comes to life. The figure is a life force called Orichalcum ("Oriharukon") that fulfills the wish of its creator. Their strange life together begins
From mangaupdates.com

The story drags us into the daily life of Mashiro, a handywoman, who takes care of helping the people of the village. One day, the Dominantor Empire invades the region and captures all the women to make them their slaves. When her friend dies before her eyes, Mashiro, mad with anger, manages to wake up the millennial robot who was secretly residing in the village. It is now her chance to stop the thirst for uncontrollable power of the Dominator Empire. Soon, she is joined by other mecha pilots in this crazy quest to oppose an entire Empire.

(Source: MU)

Souki Hiiragi was a normal small town boy whose only desire was to make cute girls happy. But one day at the beach he gets caught up in a giant robot fight! One robot attempts to defend him; this robot is the Jinki--which requires two operators to run properly. One operator sacrifices himself to save Souki, but now the other operator needs a partner! She being a cute girl, Souki steps up to the plate!

In the midst of a firefight to save a hostage from religious fanatics, Yuri, a member of the police force, steps forward to challenge them "alone" but when his comrade Mia intervenes to aid him, things only get stranger.
As Mia attempts to evade her superior's criticism over her methods, she collides head on with the Mad Scientist, Doctor Over. The Doctor seems fascinated by her, and as his inhuman army attacks Mia and her allies, she finds herself trapped. As an unusual blade pierces her chest she thinks she's going to die... but it seems that this is only the beginning.

The prequel to JINKI: Extend, which basically tells the story of a 14-year old, robot modelling girl named Tsuzaki Aoba. She encounters a giant JINKI robot type, called the Moribito-2, and ends up fighting against ancient JINKI and an unknown force. (Source: M-U)