Ghostly push

My reason

The reason why i have those items and skill for build one is because you should be tank-ish and have good survivability to push just in case you get ganked and witchcraft is very useful in this case allowing you to have more spirits and the spirits will heal you after the effect and do damage to the tower if used near tower and during team fights they will wreck your enemies plus you will need the mana regeneration from bloodstone because you can be very mana hungry which witchcraft helps prevent too.

my reason for built two is you can play a little bit more support but you should still be able to push very well and boots of travel can make it where you don't have to carry a teleport scroll but can still be tank-ish and bloodstone is just very useful on Death Prophet (Krobelus).

Team Fights

Team fighting with exorcism is a must have playing Death Prohpet (Krobelus) and try to hit people with the your locust swarm (Skill shot) as much as possible and make sure your spirits are hitting them because if you just stand on the side of battle sometimes your spirits wont go after the enemy heroes but you should be fine do to your regeneration and if your ult last you will be healed fully most likely.

Goods and Bads

Good

.Amazing pusher
.Very useful in team fights
.Good healing from ultimate
.Area of effect damage
.Has silence

Bad

.Sometimes gets focused
.While pushing gets ganked
.Ultimate has 90 second cooldown (Exorcism)
.Ultimate only heals after 30 seconds

Pushing

To push you want to have Exorcism and enough mana to use it after using locust swarm, to push you should first cast Locust Swarm on the minions to get damage and lower them a lot, keep doing this until you get to the enemy tower and then cast Exorcism but remember if minions come up you sh ould Locust Swarm the minions to weaken them and then take them out so the tower doesn't attack you if it does back up a little them come back to the tower and wreck it with Exorcism.