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all intervention do the last one (not the bridge woes, that is dlc). link: All intervention

True Ending I grinded a bit for you and there is resist confusion and oblivion mirajewels on lann/reynn. Talk to Serafie and say yes for final battles, standard stuff except last (5th) boss battle you need to spam spellstones and bring out mega mirage bahamut when he is at 2 on countdown to absorb damage, then you can use megaflare and resume spellstone spam.
link: True Ending

Brave new dungeons trophy it is right before the last boss, standard stuff again spam shantotto and/or spellstones and heal when needed. link: Brave New Dungeons

This save is for alot of trophies. First off you are put right before XG cogna for that trophy, it is a little bit of a pain, you can use shantottos champion and spam spellstones/use bahamut and mega phoenix when she kaishins a character and stack back up when you can. Plenty of turbo ethers and some elixirs so spam items and you should be able to win. Next trophy for adding tamomohime to roster just go to a save point and replace a mirage with tama and then press start over tama and transfiguration to tamomohime, trophy will pop. Next trophy is people pleaser now that you have tamomohime complete the mirage hunter quest in adventure log, but I messed up and you will have to go to cornelia as well and talk to question mark right outside and go kill 8 goblins in watchplains (very easy) then it will pop. Last trophy is secret areas, pull up world map and go to ends of grymoire and use the furthest purple crystal when you go into castle exnine, then just go north and use the metal gate and keep going and it will pop. Oh and it's also for last murkrift mirage just touchpad then square then square again for airship and go lower left part and enter and defeat it. Link: XG,Tamomohime,People Pleaser, secret areas

All chests- press touchpad and square and select watchplains... now follow this video until chest 7, you'll have to pick up 3 chests but alot better than going through all.