Mind Blank as listed would for sure stop the Truesight spell, because it is a divination spell and per the phb pg 259- 260

one willing creature you touch is immune to [..], Divination Spells

but the Monster sense of Trusight is not a spell (Divination or otherwise). It is a special sense, per MM pg 8-9

SENSES

 

[..] Special senses are described below.

 

[..]

 

Blindsight

 

[..]

 

Tremorsense

and so on...

But the tricky part is that the Mind Blank spell also says

The spell even foils wish spells and spells or effects of similar power used to affect the target's mind or to gain information about the target.

emphasis mine

So, are a monster's special senses "effects of similar power used to affect the target's mind or to gain information about the target"?

This becomes a big question when players start using Mind Blank in conjunction with Greater Invisibility.

Mind Blank as listed would for sure stop the Truesight spell, because it is a divination spell and per the phb pg 259- 260

one willing creature you touch is immune to [..], Divination Spells

but the Monster sense of Trusight is not a spell (Divination or otherwise). It is a special sense, per MM pg 8-9

SENSES

[..] Special senses are described below.

[..]

Blindsight

[..]

Tremorsense

and so on...

But the tricky part is that the Mind Blank spell also says

The spell even foils wish spells and spells or effects of similar power used to affect the target's mind or to gain information about the target.

emphasis mine

So, are a monster's special senses "effects of similar power used to affect the target's mind or to gain information about the target"?

This becomes a big question when players start using Mind Blank in conjunction with Greater Invisibility.

Mind Blank as listed would for sure stop the Truesight spell, because it is a divination spell and per the phb pg 259- 260

one willing creature you touch is immune to [..], Divination Spells

but the Monster sense of Trusight is not a spell (Divination or otherwise). It is a special sense, per MM pg 8-9

SENSES

[..] Special senses are described below.

[..]

Blindsight

[..]

Tremorsense

and so on...

But the tricky part is that the Mind Blank spell also says

The spell even foils wish spells and spells or effects of similar power used to affect the target's mind or to gain information about the target.

emphasis mine

So, are a monster's special senses "effects of similar power used to affect the target's mind or to gain information about the target"?

Mind Blank as listed would for sure stop the Truesight spell, because it is a divination spell and per the phb pg 259- 260

one willing creature you touch is immune to [..], Divination Spells

but the Monster sense of Trusight is not a spell (Divination or otherwise). It is a special sense, per MM pg 8-9

SENSES

[..] Special senses are described below.

[..]

Blindsight

[..]

Tremorsense

and so on...

But the tricky part is that the Mind Blank spell also says

The spell even foils wish spells and spells or effects of similar power used to affect the target's mind or to gain information about the target.

emphasis mine

So, are a monster's special senses "effects of similar power used to affect the target's mind or to gain information about the target"?

This becomes a big question when players start using Mind Blank in conjunction with Greater Invisibility.