Beginning And Skills
Beastmaster is easily one of the most fun mid heroes to play. I would classify Beastmaster as a ganking and pushing hero. Beastmaster is a slightly micro intensive hero, so I do not recommend him for new players. Before we go into the bulk of this guide, we need to look at beastmaster's abilities.
Wild Axes: His best ability besides his ultimate. This is a simple AoE nuke that curves outwards when you use it, curving back inwards towards the targetting point, then returns to you in the same pattern. This ability can hit the same target twice and has a very impressive range (1300 at all levels). This ability does 90/120/150/180 damage for each axe with a cooldown of 13 seconds, so being able to aim them can make all the difference. While laning mid, this ability will be your main farming tool, seeing as beastmaster is melee.
Call of the wild: This ability allows you to summon one creature at first, and 2 creatures at level 2, 3, and 4. It costs 25 mana at all levels, making this an ability you can always have up. At all levels it summons a hawk which has a very small vision range at early levels, with a very large vision range at later levels. What makes this hawk so good is because it has clearvision, making so tree can never obstruct its vision. At later levels, the hawk also becomes invisible when it is sitting still. The hawk is very important for laning because it can scout runes for you. With your bottle, this allows you to easily keep your mana up to keep spamming wild axes. The second half of this ability summons a boar at level 2 and beyond, allowing you to last hit from range with him, although his attack damage is very low at early levels. The boar also gets a slowing effect on its attacks allowing you to chase enemies a lot easier.
Inner Beast: Not the greatest of early abilities but it allows you to easily push down towers. Combine this with your summons and you can become one of the best pushing heroes. I never would recommend picking this up early unless you are going to super push very early on.
Primal Roar: This ability is what makes Beastmaster so boss at ganking lanes. This ability is one of the longest single target stuns in the game at higher levels (2/3/4 seconds). This ability also pushes other nearby enemy champions out of the way and does a little damage to them as well. The ability has a decent cast range (600), so it usually best to try and come from the side, or the bottom of enemy heroes to flank them with it. This ability also bypasses bkb, allowing you to not have to worry as much about an enemy carry. Also, the cooldown on this ability is relatively short (80/75/70).
Beastmaster is a very strong mid because he can easily rune control with the right playing. Your starting items leave 350 gold left over so you can easily get a very early bottle and start rune controlling. As long as you are spamming Wild Axes, you are winning the lane. Runes spawn every 2 minutes, so try and keep a hawk at one of the rune spawns so you know exactly where to go when the rune spawns. If you manage to get a haste or invis rune, it is a great time to go gank top or bottom. Basically laning mid with beastmaster boils down to controlling runes and knowing when to gank. If you are against a ranged character that can easily harass you, try and keep spamming wild axes for last hits and if needed, level call of the wild to level 2 and level 3 so you can get your boar to last hit for you.
Mid game you should be roaming around the map looking for ganks for your carries. YOU ARE NOT A CARRY, do not spend tons of time farming, simply farm a wave or 2, here and there then move on. You should always be looking for a lane to gank or a tower to push. If you are doing well, you should have a necro book by now allowing you to easily push towers. Also, always use your hawk to scout for you to make sure it is safe for you to push a tower or gank a lane. Beastmaster is a very mobile hero mid-game, so don't expect to be in one spot for too long.
Beastmaster can be a psuedo initiator late game for any teamfights that start. You can single out the enemy team's carry with your roar, effectively removing them from the fight for 4 seconds. This also helps your team get to the enemy carry to quickly burst them down (unless they are a really tanky carry like spectre). Late game, you should be thinking about pushing and singling targets out for your team. If you did your job early and mid game, your carry should be farmed enough to win the game for you.
Beastmaster is an extremely fun hero to play if you use him correctly as he is a very versatile hero, able to fill many roles at once. Since he is such a mobile hero, it makes him a great fighter, able to pick off heroes if they choose to be alone. I will most likely be editing this guide at a later date as I become better at this game.