Head forward and destroy the three guards you find. Continue on and you'll be in a big area with four guards: two ninja bots and two mace guards. A Blast move really helps out here. Gather the sunstone from the lower corner and break the nearby wall for more relic parts. Mop up the guards to release the gate.
Just past the gate, look to the right for another brittle wall leading to:
HIDDEN CHEST #28:
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
After battling the four guards at the beginning of the chapter, check the right wall for a breakable section and destroy it to find this chest.
Head forward for a scene.
Once you regain control head forward and take out the guards. Further on grab the relics but note the crossbow guards are shooting at you (so don't relax!). Go take them out and in the next room is a mace bot. He will shoot his mace at you, so be sure to dodge it (the game will help if you are far enough away). Two ninja bots will come down after that, so take them out as well and collect the relics. Now before going further, note the archway on the right here. Destroy the wall for:
HIDDEN CHEST #29:
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
After your fight with the mace-bot and the two ninja bots with spears, look for an arch on the right. Break the wall to uncover this hidden chest.
Continue on and gather all the wood you find along the way. You will grow to be quite massive now! When you are on the rampart, go press against the north side of the building to climb it, then take out the guards at the top (one hit - easy). Gather more wood and climb up the next building (don't worry about the archers: being on fire is OK). This ends this part of the chapter.