To Obtain Fuka's Epilogue you must:
1) Complete the first 9 episodes
2) In Episode 10 Complete Stages 1-6. DO NOT COMPLETE 10-7 which is the final stage
3) If you haven't done so already, call a Senate and unlock the "Legendary Tree" Evil Symbol and place it somewhere on the map in Cam-pain so all squares are visible. The Pattern is +.
4) Go back to Base and Save your game. You have multiple slots so what I did was save the game in slots 1-5. Only one epilogue can be unlocked perm playthrough which is why we use multiple saves
5) Go back to the Cam-Pain
6) Place Valvatorez on the L square and Fuka on the one of the other 2 squares. The middle DOES NOT count.
7) Hit LT or whatever button it is to "Dispatch an evil deputy" and walk up to the Legendary Tree and hit the Action button to interact. Set Fuka to "Mentor"
8) Go back to the Base and Save your game to one of the 5 Slots you saved Earlier but ONLY ONE. (You can also change your save icon in settings to the character you doing the Epilogue for in Settings to make it easier to identify saves)
9) At this point Quit and load up one of the other saves and repeat steps 5-8 for each character. So once you are done, you will have 5 Saves with all 5 characters set up at the Legendary Tree. Skip if Completed already through one of my other Epilogue Guides
10) Now each character has a specific requirement to unlock an event needed to get the epilogue. Check each characters achievement for their individual task. Fuka's is to have Valvatorez use one of her Spells. She can learn Target Lock at the Evility Shop. I do not know if she learns any other spells that are shareable
11) Load up Episode 1-5. I like this map because it has a Mage which makes it much easier to use the skill. Bring out Valvatorez and Fuka. Send Valvatorez to an enemy and put Fuka right beside him. You can now see Target lock at the bottom of Valvatorez's Special List. Use it. The enemy will attack on their turn and be killed by the counter attack but that wont be a problem with the mage so just rinse and repeat the skill with the enemies until the Counter kills all but the Red Skull Mage. The Mage will always retreat and use a spell so you wont counter and you can keep him alive as long as needed. You need to use Targetlock or any other spell of Fuka's if any exist 10x.
12) Once you used the spell 10x, finish the Stage and go back to Cam-Pain. You should get a prompt that an event has occurred under the Tree. Click through the prompts to go through the scenes
14) Now Complete 10-7 and you should unlock the Epilogue after the Credits.
15) You will be prompted to Save after the Epilogue. You can choose to do so if you wish. Obviously only save to the dedicated save for that character if you do.