Not an issue that bothers anybody.

Because the Zeal is one item. Nobody cares that the artwork looks like 2 blades.

When you combine 3 items, you get a trinity. Thus, the trinity force.

Because then it wouldn't be a Zelda reference.

Also the trinity force has 3 blades in it. So it's got the 2 zeals and sheen (If your going to complain check these things first). What you might be complaining about is the lack of phage in there but in reality who cares it's trinity force and that sounds, looks and just is better than quadraforce and it's still made of 3 parts to be considered trinity.

Phage gets destroyed in the process of making it, imbuing the blades (which are WAY cooler than mallets) with its power.

also... I always imagine my character running around with the Zeal-Blades in each hand and sheen in their teeth >.>

Phage is the hammer that forges Zeal and Sheen together.

...Yeah. Let's go with that.

Disclaimer: This may not actually be true.