When the mission begins, drop down and go up to the guard, pickpocketing his key. Now you have the key, go to each side and unlock the roller. Run on the roller until the dragons open their mouths, then use your Samurai armor to reflect the fireballs back at them, which will unlock the Dragon Gates. Once it's open, go to the entrance to begin the next part.
Just run forward until you meet with El Jefe on the bridge. You'll have to defeat 15 guards here with Murray, who will fly in from above. If you got some of the upgrades and abilities from ThiefNet, then you shouldn't have too much trouble here. Once the last one is defeated, you'll switch control to Rioichi Cooper.
With Rioichi, you will have to do some simple platforming. It mostly involves using the Leaping Dragon to jump from point to point, then jumping on small platforms. There's also two spots where you need to walk along a thin ledge. Once you get to the rope at the end, jump underneath the bridge and use the roller to open the gate above.
After a short cutscene, go forward a little bit until another comes up. El Jefe steals Rioichi's cane and destroys the bridge, but you'll now be in control of Sly. Use the points to get across the broken bridge, then go through the newly opened door and grab the Secret Sly Mask in the left corner as soon as you pass the doors. Go up to the marked door and go through it, which will trigger a cutscene and then the boss fight against El Jefe begins.
FACE TO FACE WITH EL JEFE
The boss fight with El Jefe is split into three parts, with the same setup each time. When it begins, he will shoot fireballs at you from afar, while you walk on tightropes. Getting to El Jefe will make him run away again, triggering another platforming section. When you get to the end, climb the pole and the first battle portion will begin.
El Jefe follows a pattern in each phase for the entire fight. For the first phase, El Jefe will start by slamming both his swords into the ground, causing a shockwave to spread out from his position; simply jump over this. His next move has him forming a giant lightning sword (called Lightning Sword) and swinging it to the ground, then rotating it towards your position. As long as you keep running in one direction, this attack can be avoided.
After the Lightning Sword attack, he will use a lightning sword to swipe from one direction, across the ground (called Swipe). Sometimes, he will do this twice in a row, from both directions; you can simply jump over this attack. After this one, he will smack his swords one at a time on the ground, then shoot a fireball (Fireball) at you. You need to equip your Samurai armor and deflect it back with the shield. If done right, El Jefe will be stunned and you are free to hit him with your cane (unequip the Samurai armor as soon as you deflect the fireball). After the fireball, he will start over from the beginning.
Once you do enough damage in the first phase, there will be another short platforming section. El Jefe gains two new attacks in the second phase. While there was a normal shockwave in the first phase, this time it will be a giant wall of fire, so you'll need to equip your armor to avoid damage, then unequip it for the next attacks. He will summon electricified spheres in the shape of a plus sign around him, then do his Lightning Sword attack. After that will be one or two Swipes, then a Fireball.
When you get his health to a certain point again, he will run away and there will be yet another short platforming section. The third, and final, phase will begin with the same attacks as the second phase. After the first time doing this, he will switch it up a little bit. He will start with the wall of fire, then he will extend both blades out with electricity and spin around; single jump over these, as double jumping will likely make you land on one. He will do a Swipe or two after that, then the Fireball. Deplete the rest of his health and El Jefe will be defeated, signaling the end of your trip to Japan.
