This is a combiner model. It has no storyline significance.
In March 2016 instructions were released on BIONICLE.com to combine the two sets into Twotoa 2.
|BIONICLE Combiner and Alternate Models of 2016|
|Combiner Model||Twotoa 1 | Twotoa 2 | Powered-Up Umarak|
|Other Models||Shadow Spawn | Shadow Titan Makuta|
|see full list|
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