Edit 1: Game of Fate

[The Four-Eyed Cat]

Every week of the year a card is played, here as elsewhere, removing "the" and some other words could aid rhythm at the expense of making the work more explicitly poetic
four suits as the seasons tell. as noted, a colon here would make the rest dependent on the main metaphor (and explain lack of capitalization)
seers seeking signs and omens nice alliteration - note how well this works with no "the"
for soldiers gambling their lives. perhaps semicolons for these periods?
hearts bleeding for a king’s ideology,
blood red queens and diamonds. if you could work in "blood diamonds" this could be contemporary
spades digging trenches and graves of war not to mention latrines - always latrines (g)
for infantry boys bearing black clubs, lances and rifles
causality cutting lines and making all equal in fate perhaps verbs here - "causality cuts..."
kings and commoners playing with the hand they’re dealt as above, perhaps "play" vice "playing"
knowing they might not see the deck being shuffled again concluding line... needs simplifying, and a period IMHO

Must admit, I had difficulty finding a rhythm to read this aloud.  Perhaps in the editing process you could try for something galloping or marching or even zzzzip-bump, zzzzip-bump for cards being cut and dealt.  Just a thought.

Another idea - just a suggestion - would be reference to the simple card game of "War" since most of the references are to that rather than other fated activities.

My main confusion was following the grammar/punctuation.  Replacing the first period with a colon, most of the commas with semicolons, and then a period at the end would fit the capitalization and clarify the structure - for me, anyway.

Other comments above.  It's a good conceit, with appropriate examples given.  One last thought:  the deck is really fifty-four, you know... two Jokers.  What would they be, Christmas and Easter truces that surprise all the generals?

Many comments, but this is a good metaphor that will reward editing.

Thanks for the comments, I'll certainly pick them up and incorporate many of the suggested changes into my edit. 
Regarding your suggestion on the game 'war', it's the first time i've heard of it - so i'll have to do some research on how the game really works (although a quick wikipedia browse already yielded quite some results) and how i should incorporate it.

Regarding the deck being 54, the 'original' decks didn't have them, and many games consider the jokers to be unnecessary cards. It's the excuse i'll be rolling for, since there are 52 weeks in a year and that's the coincidence that made me want to write this poem in the first place 

Also, do you have some suggestions for that last line? as it is really cracking open my skull!