keeper of the forest is a slightly weaker version of the tree in dota.
decent hero in teamfights with his ulti as well as provides maphack with his tree sight.
key differences from the tree in dota.
-he has lower base damage, and a third skill which can give him up to +60 damage for 5 hits (sucks)
-his eyes in the forest cannot see invisible units, however they give passive regeneration to the units around them
camoflage is a great spell at level 1, you never know if you're going to be ganked at level one, even if you get tree sight first.
tree sight early is such a good spell, it's incredibly hard to gank tree when he has tree sight placed right, and it can be used near runes too for great early map vision.
nature's vengeance is necessary because s2 owned tree's base damage and now he needs to go this if he wants to last hit in lane. it is necessary to max this spell after one point in camo/tree sight and root.
why i don't max camo until later - you really only need one level in it, it has 0 fade delay for invis with a fairly low cooldown and it lasts a decent amount of time. it's also easily countered, i prefer stats to maxed camo personally but this is all about personal preference. consider going another point in it if you're glorify, it's a solid skill.
1x runes of the blight
1x healing potion
2x pretenders crown
2x fortified bracelet
steam boots (str)
mock of brilliance
why get mock of brilliance?
it's great for farming and with nature's vengeance (+60dmg lol) it's not hard to farm enough for it against a lane.
after mock of brilliance he can pretty much go anything. restoration stone is great for him because with it he can cast his ulti twice in a row. if you go restoration stone make sure you change your steam boots to int, so he has enough mana to use his combo.