"Who started WW I and II?"

Well...that's a bit complicated. Let's start with WWI.

It's a bit tricky saying who "started" that one, because it was triggered off by two sets of entangling alliances and what we would today term a terrorist assassination.

The Serbs were attempting to separate from Austria-Hungary. (that's the sort of ethnically-driven argument that has been going on in the Balkans since time immemorial) The Austro-Hungarian government did not approve of Serbian secession from the empire (SURPRISE!)...when does a large empire or government EVER approve of some part of its territory seceding? Americans killed 500,000 of each other over such a dispute in the Civil War.

A fanatical Serbian nationalist assassinated the Austrian Archduke, who I believe was the heir to the Austrian throne. This infuriated the Austrians and war became inevitable at that point...war between Serbia and Austria-Hungary, that is.

One little problem! Russia had an alliance with the Serbs, that if anyone attacked them then Russia would declare war on that power. So....

1. Austria-Hungary declared war on Serbia
2. Russia declared war on Austria-Hungary

A further little problem! Germany had a similar alliance with Austria-Hungary, so Germany declared war on Russia.

And yet a further little problem! France and the UK had an alliance with Russia, so France and the UK declared war on Germany.

Now....who is to blame for all that? They were all to blame as far as I can see. They all stupidly stumbled into a hideous world conflict and none of them could possibly have imagined how long it would last and how much suffering it would cause.

You cannot blame any one country for starting that war, though it is always fashionable for the winners to blame the losers once it's over, right? (So I would assume you were somehow blaming Germany for the whole thing? Or was it someone else?)