Landlord-tenant law for Manitoba is freely available online. You need to read it whether you're a landlord or a tenant, because you have rights and responsibilities pertaining to either your use of someone else's property or to someone else's use of yours.
Last I checked, which was a long time ago, landlords were not allowed to take more than 1/2 a month's rent as damage deposit, and it had to be placed in an interest-bearing account for the duration of the tenancy. All deductions from the damage deposit have to be documented. At the start of the tenancy, an initial inspection needs to be done, and both landlord and tenant need to sign off on what damage is already there prior to the tenancy starting. If there is no initial walk-through inspection, the landlord has no legal ability to say that the tenant caused any damage.
There's a lot of stuff about damage deposits in the act. Please read it.
https://web2.gov.mb.ca/laws/statutes/ccsm/r119e.php