Union monsters are interesting since they can offer a lot of support to a deck, but can sometimes be dead draws. However, there are some very good unions out there, for instance
Machina Gearframe is a crucial union monster to the machina archetype, because it can be used to search out Machina Fortress, then, when you get fortress on the field, you can use gearframe to protect fortress, even better than before; this means that with its own defencive effects your opponent will have a very ahrd tiem killing it. You can also use gearframe as a high attack beater when there is no need for defendign fortress.
Here we go again, make it more active than last one please.
Spoiler :
Machina Gearframe is a crucial union monster to the machina archetype, because it can be used to search out Machina Fortress, then, when you get fortress on the field, you can use gearframe to protect fortress, even better than before; this means that with its own defencive effects your opponent will have a very ahrd tiem killing it. You can also use gearframe as a high attack beater when there is no need for defendign fortress.
Here we go again, make it more active than last one please.