Wall of text, no bbcoding, little explanation behind your summoner spells/Item choices.
Not downvoting yet, but please work on that :)

It's a wall of text. If you want to improve this guide I suggest looking at Jhoi Jhoi's Making a Guide. You have no coding/pictures/videos.
Maw of Malmoritus is situational, you should add alternatives as well to your build.

If you fixed this up, it could be good.
But, as is it's lacking a ton of information.

I won't vote, but some suggestions:
Look into Making a Guide by JhoiJhoi
Learn BBCoding
Add images/videos
Check grammar
Add alternatives to runes/masteries/items

Good luck :)

riven is not a tank. she just isnt, offtank you could argue but tank, no. her main strength comes from her manuverability and her bouncy thingy. couple this with attacks inbetween and you will do just fine.
maw of malmoritus is a more situational item, used against a heavy AP burst character. i could go more indepth to why the skills and items are wrong, but i really dont have the time or effort to do so. i dont see an atmas anywhere.
asthetically speaking its very bland, short, and no really good info.
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