This secret mission is found at the very end of Mission 14, in Forest Entrance, the room that leads to the tunnel to the waterfall. After passing the Red Orb Crystal, go into the gazebo with the stone tablet: the paper for the secret mission is found on one of the pillars.
This mission takes place in Customs House, the area leading to the bridge controls from Mission 2. The goal of this secret mission is to perform five sequential royal (perfect) blocks while using Royalguard Style. A royal block is indicated by a larger flash effect and louder sound. Taking a hit or executing a normal block will reset the counter, but will not fail the secret mission: running out of health is also not marked as a fail state, meaning if Dante dies in this secret mission it counts as a death in the mission itself. Evading attacks does not reset the counter: the royal blocks need to be an unbroken streak, but do not need to be blocks against sequential attacks.
If the level 4 Royalguard ability "Dreadnought" is active (making Dante invulnerable while draining the Royal Gauge), taking hits will not reset the counter.
Mephistos have four attacks. The first two are close range, the latter pair long-range.
- They circle around the player character before holding up one hand and, with a distinct zipping sound, draw in power and then extend their finger in a quick stab.
- They spin around on the spot, lashing out with the claw at the tip of their tail. This is performed at very close range, and may be performed multiple times in a row.
- They back off, rise up into the air slightly, and perform a fast lunge attack.
- They back off and perform a spinning attack that turns their body into a wide form resembling a buzzsaw, then move towards the player character. This move is rare, and it is best to avoid it.
The first thing to do is kill one of the Mephistos, as this will mean the player only needs to focus on one of them.
The spinning attack is the easiest to guard. The Mephisto will spin around, lifting its tail and fanning its cloak as it does. Just before it swings the tail around, it will pause. Wait for that moment, then press the style button. It is imperative to wait until the Mephisto pauses, as preempting the pause will cause Dante to block too early.
The second easiest Mephisto attack to block is the extending finger. Listen carefully to the attack. The Mephisto's finger will glow while it charges the attack. There is a distinct audio cue which rises in pitch. When the cue has reached the highest pitch, press the block button and Dante should execute a Royal Block. It can also be timed visually: look between the Mephisto and Dante and press the style button the instant the finger stands to extend.
The charging attack is, perhaps, the most difficult to time. The Mephisto will swoop back to put distance between itself and Dante. Depending on the camera angle and Dante's position within the room, it may end up out of sight, either through a wall or behind the camera. If this happens, Air Hike or Trickster dodge to avoid ruining the streak. If it is still in view, wait for it to extend its claws and drop to the ground. Once it does this, wait a split second before blocking. As with the spinning cape attack, if the player tries preempt the drop, Dante will block too soon.