The four hidden puzzle pieces in Universal Tower Defense Z are the awkward middle step of the Despair of Defeat trial, the questline that hands you the secret Isagi unit known in-game as The Egoist. The first piece is easy to walk into. The other three are tucked into corners, rooftops, and underpasses that you would never pass by accident, which is exactly why the trial stalls for most players here.
Quick answer: The four puzzle pieces sit inside the World Train subway platform, on the rooftop of the building next to the Luffy/Rubberman NPC, on the sidewalk under the Event area bridge, and inside the parking lot compound by the Mysterious Witch NPC. Collect all four, then claim the step in the Despair of Defeat trial to receive The Egoist.
Start the Despair of Defeat trial first
The pieces only count toward the trial once it is active, so open the quest before you go searching. Talk to the Footballer NPC standing at the entrance to the World Train, in front of the green door. This begins the Despair of Defeat trial, which runs through five separate objectives, with the puzzle hunt sitting in the middle.
Make sure the game is updated to its current version before you begin. If your client is out of date, the puzzle pieces and the trial itself may not appear in the lobby.
| Trial step | Objective |
|---|---|
| 1 | Talk to the Footballer NPC in the lobby |
| 2 | Score 10 goals in the Football gamemode |
| 3 | Find the 4 hidden puzzle pieces around the lobby |
| 4 | Win the Football gamemode with 5 Boundless units on your team |
| 5 | Evolve Blue Rose |
Where to find all 4 puzzle pieces
Each piece is a separate blue collectible, and the order you grab them in does not matter. Walk directly into a piece to pick it up. A notification confirms your running total, from “Puzzle Piece collected! (1/4)” up to “All Puzzle Pieces found! (4/4)”. Keep count so you do not waste time re-checking a spot you already cleared.
World Train subway platform
Head to the World Train point of interest, directly opposite the Summon area. This is an underground metro station, so climb down the stairs to the platform. Turn toward the train and follow the narrow walkable path along the yellow safety line to the far corner. The piece is waiting on the platform floor, near a pillar under the World Train sign.
Rooftop next to the Luffy/Rubberman NPC
This is the trickiest reach. From the Footballer NPC, move right until you find the Luffy (Rubberman) NPC. Climb the building next to him to get the piece resting on a raised platform at the top. Use the metal side stairs to gain height, then jump onto the outer ledge and work up the sloped roof beams. Time your double jump and directional input carefully, since the final hop onto the roof is what stops most players.
Under the Event area bridge
Go to the Event area bridge, where you will see two staircases. Take the left staircase down to the sidewalk beneath the bridge. The piece sits in this red-lit underpass, next to the shuttered shop with the electric panels on the wall.
Parking lot compound by the Mysterious Witch NPC
Make your way to the Play & Extras area, then walk straight ahead to reach the Mysterious Witch NPC. Step inside the fenced compound, which holds a police car and a white van marked “Universal Tower Defense.” The final piece is tucked in the corner behind the vehicles, next to the cop car.
Claim the reward and unlock The Egoist
Collecting all four pieces does not hand over the unit on its own. Once the “All Puzzle Pieces found! (4/4)” message appears, open the Quests menu on the left side of the screen and go to the Trials tab. Select Despair of Defeat and press Claim on the “Find the 4 hidden Puzzle Pieces around the Lobby” step.
The claim triggers an “Items obtained” pop-up. Clearing this step delivers the following rewards:
| Reward | Amount |
|---|---|
| The Egoist | x1 |
| Gems | 10,000 |
| Stat Locks | 30 |
| Trait Rerolls | 50 |
You know it worked when The Egoist shows up in your unit inventory. From there it slots into your team like any other collectible unit, ready for Story Mode, Blitz, or event raids.
Why a puzzle piece won’t register
If the trial still reads fewer than four pieces, the pickup for one of them never triggered. Back away from that spot and walk into the piece again so the collection prompt fires, then watch for the counter to tick up. A piece only counts once the pickup actually registers, so a fresh approach usually fixes a piece that seemed to be missing.
The most common cause of a stuck step is simply an incomplete count, so return to the lobby and re-check the location you skipped rather than restarting the trial. With all four secured and the step claimed, The Egoist is yours and the Despair of Defeat trial moves on to its next objective.
